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R  A425  P93  1919    Hygiene  and  public  h 


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College  of  ^i)j>gician£f  anb  burgeons 


S^tltvmtt  Hibrarp 


HYGIENE 


PUBLIC  HEALTH 


BY 

GEORGE  M.  PRICE,  M.D. 

AUTHOR    OF     "a    HANDBOOK    ON     SANITATION,"    "  TENEMENT-HOUSE    INSPEC- 
TION,"   "hygiene    and    sanitation    FOR    NURSES,"    "  THE    MODERN 
FACTORY,"    DIRECTOR,    JOINT    BOARD    OF    SANITARY    CONTROL 


SECOND  EDITION,    THOROUGHLY  REVISED 


LEA   &   FEBIGER 

PHILADELPHIA    AND    NEW   YORK 
1919 


COPYKIGHT  • 

LEA   &   FEBIGER 
1919 


PEEFACE  TO  THE  SECOND  EDITION. 


In  the  following  pages  an  attempt  has  been  made  to  give 
an  epitome  of  Hygiene  and  Public  Health,  a  subject  so  vast, 
and  embracing  so  many  correlated  branches  and  sciences, 
that  the  work  of  epitomization  is  especially  difficult.  Personal 
hygiene  has  been  entirely  omitted,  and  some  subjects  of 
public  health,  upon  which  volumes  have  been  written,  have 
been  disposed  of  in  a  few  lines  or  a  few  pages.  It  has  been 
the  aim  of  the  author  to  give  the  essential  parts  rather  than 
cover  the  whole  field  of  the  science. 

For  the  second  edition  a  number  of  changes  have  been 
made  in  the  text  whenever  required  to  bring  the  work  up  to 
date.  The  most  important  changes  were  made  in  the  Chapter 
on  the  Prevention  of  Infectious  Diseases,  to  which  was  added 
the  very  important  report  of  the  American  Public  Health 
Association  Committee  on  Standard  Regulations  for  the 
Control  of  Communicable  Diseases. 

G.  M.  P. 


(iii) 


Digitized  by  the  Internet  Archive 

in  2010  with  funding  from 

Open  Knowledge  Commons 


http://www.archive.org/details/hygienepublicheaOOpric 


CONTENTS. 


CHAPTER  I. 
Introduction. 


Definitions — Aim  and  Function  of  Hygiene^Sanitary  Progress — • 
Possible  Prevention  of  Disease — Economic  Value  of  Human 
Life — Questions 17 

CHAPTER  II. 

Housing  Hygiene. 

Relation  of  Houses  to  Health — Building  Materials — Fireproofing 
— House  Dampness :  Causes  and  Prevention — Building  Con- 
struction— Soil,  Sites,  and  Aspect — Foundations,  Footing,  and 
Cellars — -Walls,  Floors,  Roof,  etc. — House  Planning  and 
Arrangement  —  Lighting  —  Natural  Light  —  Artificial  Illu- 
mination— Air:  Composition,  Impurities,  Properties — Venti- 
lation: Natural,  Artificial,  and  Mechanical — Heating:  Prin- 
ciples, Means,  and  Methods;  Local  Central  Heating — Water 
Supply:  Impurities — Domestic  Water  Supply — Domestic 
Water  Purification — Drainage  and  Plumbing — Quantities, 
Immediate  Disposal  of — House  Plumbing,  Pipes,  Fixtures, 
Traps,  and  Loss  of  Seal;  Water  Closets:  Flushing — House 
Cleaning — House  Impurities  and  Health — The  Role  of  Vari- 
ous Insects  and  Domestic  Animals — Prophylaxis,  Means  and 
Methods  of  Cleaning,  Disinfection — The  Housing  Problem, 
Causes  and  Remedies — Housing  Inspection — Elements  of 
House  Inspection — Details  of  House  Inspection — House 
Dampness — ^House  Inspection  Special — Examination  of  Air 

in  Rooms — Relative  Humidity — Questions 22 

(v) 


vi  CONTENTS 

CHAPTER  III. 

School  Hygiene. 

Scope  of  School  Hygiene — The  Effects  of  School  upon  Health — 
School  Diseases — The  Causes — Prophylaxis — The  School- 
house  —  School  Furniture  —  Home  Influences- —  Feeding  — 
Regulation  of  Hours  of  Study — Methods  of  Study — Rational 
System  of  Teaching — Promotion  of  Health — Isolation  of 
Defectives  —  Prevention  of  Infectious  Diseases  —  Proper 
Medical  School  Inspection  and  Supervision — Questions     .    .       67 

CHAPTER  IV. 

Industrial  Hygiene. 

Definition,  Scope,  and  Functions — The  Value  of  Statistical  Data 
— The  Causes — Personal  Factors :  Sex,  Age,  Place  of  Work — 
Adverse  Industrial  Conditions — Dust,  Poisons,  Gases,  and 
Fumes — Infectious  Materials — Hazards  and  Accidents — Pro- 
phylaxis— Sanitation  of  Workplaces — Prevention  of  Dust — 
Prevention  of  Conditions  Due  to  Poisons,  Gases,  and  Fumes 
— Personal  Prophylaxis — Restriction  of  Female  Labor — 
Child  Labor — Home  Work — Prevention  of  Effects  of  Fatigue, 
etc. — Prevention  of  Accidents — Medical  Factory  Inspection 
— State  Insurance — Questions 80 

CHAPTER  V. 

Public  Water  Supply. 

Water  Supply  and  Public  Health — The  Parasitic  Ova  in  Water — 
Bacteria  in  Water — Water-borne  Diseases — Sources  of  PubHc 
Water  SuppUes — Water  Purification — Filtration — Sand  and 
Mechanical  Filtration — Water  Inspection — Water  Inspection 
Microscopically — Water  Inspection  Bacteriologically — Chem- 
ical Examination  of  Water  —  Sanitary  Inspection  of  the 
Sources — Significance  of  Various  Ingredients  in  Water — 
Questions 109 


CONTENTS  VU 

CHAPTER  VI. 

Food  Supply. 

Food  Supply  and  Public  Health — Meat  Foods — Entozoa,  Bacteria, 
Toxins,  and  Ptomains — Animal  Diseases — Condition  of  Ani- 
mals— Postmortem  Changes — Adulteration — Prophylaxis — 
Animal  Hygiene — Antemortem  and  Postmortem  Inspection — 
Sanitation  of  Places  and  Hygiene  of  Persons — Preservation 
— Sanitary  Supervision — Poultry,  Fish,  etc. — Other  Foods — 
Questions 120 

CHAPTER  VII. 

Milk  Supply. 

Milk  Supply  and  Pubhc  Health — Milk  and  Infant  MortaHty — 
Milk  and  Diseases — Sources  of  Impurities — The  MUk  ^Animal 
— The  Place — Individuals — Utensils — Water — The  Chemistry 
and  Physiology  of  Milk — Bacteria  in  MUk — Changes  in  ]Milk 
— AduIteration^Prophylaxis :  The  Cow,  The  Stable,  The 
Water  Supply,  The  Milk  House,  The  Milk  Stores,  Utensils, 
Persons  Milking*  —  Preservation  —  Sanitary  Supervision  — 
Sanitary  Inspection  and  Examination  of  Milk — Sanitary 
Inspection  of  the  Production  of  Milk — Score  Card  for  the 
Production  of  Sanitary  Milk — Questions 137 

CHAPTER  VIII 

Disposal  of  Waste  Matter. 

Kinds  of  Waste  Matters — Amount  and  Quantity — Hygienic 
Importance — Disposal  of  Rain,  Snow,  Street  Refuse,  House 
Refuse,  Trade  Wastes,  Dead  Animals,  Human  Bodies — 
Disposal  of  Sewage:  Disposal  into  Rivers,  Lakes,  and  Seas 
—  Filtration  and  Irrigation  —  Bacteriological  Methods  — 
Questions ..,,..     16^ 


VIU  CONTENTS 

CHAPTER  IX. 

Public  Nuisances. 

Definition  —  Noise :  Causes  and  Prevention  —  Smoke  —  Dust  — 
Waste  Matters — Gases  and  Fumes — Odors  and  Effluvia — 
Offensive  Trades — Keeping  of  Live  Animals — Ealling  of 
Animals  — Sale  of  Animal  Matter  —  Manufactiu'e  of  Animal 
Products — Questions 178 

CHAPTER  X 

The  PRE-^rENTioN  of  Infectious  Diseases. 

Definitions — The  Morbific  Agents — The  Portal  of  Entry — Modes, 
Vehicles,  and  Agents  of  Infection — Prophylaxis:  Immunity, 
Natural,  Artificial,  Acquired — Prophylaxis  by  Means  of  Social 
Measin-es — Disinfection  and  Destruction  of  Germs — Control 
of  Conununicable  Diseases — Questions        190 

CHAPTER  XI. 

Federal  Hygiene. 

Sanitary  Legislation  and  Administration — Scope  of  Proposed 
National  Health  Department — Vital  Statistics — Quarantine 
— Naval  Hygiene — Mihtary  Hygiene — Questions  ....     257 


HYGIENE  AMI  PUBLIC  HEALTH; 


CHAPTER  I. 
INTRODUCTION. 


Hygiene  is  the  science  and  the  art,  the  theory  and  the 
practice,  of  the  preservation  and  promotion  of  human  health. 

Public  hygiene  is  the  science  and  the  art  of  the  preserva- 
tion and  promotion  of  public  health. 

Personal  hygiene  is  the  science  and  the  art  of  the  preser- 
vation and  promotion  of  individual  health. 

Sanitary  science  is  the  theoretical  part  of  hygiene,  notably 
that  part  which  is  based  on  the  investigations  of  the  influence 
of  environmental  conditions  upon  health  and  the  study  of  the 
extrinsic  causes  of  disease  and  premature  death. 

Sanitary  art  is  the  practice  of  public  hygiene,  the  erection 
of  public  works  for  the  improvement  of  public  health. 

Sanitation  is  the  sum  of  practical  measures  undertaken  for 
the  preservation  and  promotion  of  public  health. 

Sanitary  law,  or  "  public  health  law,"  also  called  "  state 
medicine,"  are  terms  applied  to  the  rules,  regulations,  and 
laws  prescribed  by  state  or  municipality  as  compulsory  upon 
individuals  or  communities  for  the  preservation  and  pro- 
motion of  public  health. 

The  aim  and  function  of  hygiene  are  the  prevention  of 
disease,  the  prevention  of  premature  death,  and  the  pro- 
motion of  normal  health  of  individuals  and  the  community 
by  the  removal  of  the  causes  of  disease,  destruction  of  the 
causes,  improvement  of  environmental  conditions,  and  by  the 
increase  of  the  vital  resistance  of  individuals  and  members 
of  communities.  (17) 


18  INTRODUCTION 

The  aim  and  function  of  public  hygiene  are  the  prevention 
of  disease  and  premature  death  and  the  promotion  of  public 
health  by  the  removal  and  destruction  of  environmental 
causes  of  disease  and  premature  death  and  by  improving  such 
conditions  as  are  common  to  many  persons  or  communities. 
Personal  hygiene  in  aim  and  function  is  the  preservation  and 
promotion  of  individual  health  by  the  prophylaxis  of  con- 
stitutional diseases  and  by  the  increase  of  the  vital  forces  and 
resistance  of  the  human  body. 

The  scope  and  functions  of  sanitary  science  are  the  study  ot 
the  effects  of  environmental  conditions  upon  public  and  per- 
sonal health  and  the  study  of  the  causes  of  environmental 
diseases  and  the  promotion  of  national  vitality. 

Hygiene  as  a  modern  science  has  entered  the  family  of 
sciences  only  since  the  nineteenth  century,  and  particularly 
since  the  establishment  of  sanitary  science,  vital  statistics, 
and  bacteriology. 

Sanitation,  sanitary  art,  and  sanitary  law  are  as  old  as 
human  society,  and  date  their  history  from  the  first  common 
endeavors  of  social  communities  to  preserve  their  health  by 
framing  rules  for  guidance  in  health  matters,  and  by  erection 
of  communal  sanitary  works.        '  .        p  xr 

Great  sanitary  undertakings  are  seen  in  the  rums  of  Nine- 
veh and  Babylon;  fine  examples  of  wise  sanitary  precepts  are 
found  in  the  health  codex  of  Moses;  the  Greeks  had  made 
great  strides  in  the  art  of  personal  health  culture  by  their 
athletic  exercises,  baths,  and  gymnasia,  etc.,  while  the  still 
extant  ruins  of  the  immense  systems  of  drainage,  the  aque- 
ducts, and  public  buildings  of  ancient  Rome  call  forth  the 
admiration  of  modern  sanitary  engineers. 

But  it  is  unpossible  to  make  people  clean  or  healthy  by 
religious  precepts  or  state  compulsory  laws  alone,  or  by  the 
erection  of  great  sanitary  works,  Without  a  preliminary 
education  of  the  population  in  the  importance  of  personal 
and  public  health  and  without  a  scientific  basis  for  such  an 
education. 

Real  sanitary  progress  has  become  possible  only  since 
sanitary  science  has  shown  the  intimate  relation  of  certain 


SIGNS  OF  SANITARY  PROGRESS 


19 


extrinsic  factors  to  health,  since  bacteriology  found  some 
of  the  causes  of  the  most  virulent  diseases,  and  since  we  were 
enabled  by  the  aid  of  vital  statistics  to  prove  the  effects  of 
sanitary  improvement  upon  the  health  of  communities  and 
the  reduction  of  disease  and  death  rates  by  adherence  to 
health  laws. 

Sanitary  progress  manifests  itself  in  the  following  conditions : 

(a)  Lengthened  span  of  life. 

(b)  Decreased  mortality  rate. 

(c)  Decreased  morbidity  from  preventable  diseases. 

(a)  The  length  of  the  human  span  of  life  has  increased  over 
100  per  cent,  during  the  last  several  centuries,  the  greatest 
progress  having  been  achieved  during  the  nineteenth  century. 

During  the  sixteenth  century  the  average  span  of  life  was 
but  from  eighteen  to  twenty  years,  during  the  eighteenth 
century  it  was  a  little  over  thirty  years,  while  at  the  end  of 
the  nineteenth  century  it  reached  thirty-eight  to  forty  years. 

The  average  duration  of  life  still  differs  in  various  lands; 
thus,  while  it  was  over  fifty- two  years  in  Sweden  in  1891  to  1900, 
it  was  but  a  little  over  twenty-three  years  in  India  in  1901. 

The  increase  and  the  general  lengthening  of  human  life 

were  during  the  seventeenth  and  eighteenth  centuries  .  4  years 
During  the  first  seventy-five  years  of  the  nineteenth  century      9       " 

Present  rate  in  Massachusetts 14      " 

"  "       Europe 17      " 

"  "       Prussia 27      " 


(b)  Decreased  mortality  rate  is  shown  by  the  following; 

Death  rate  (per  1000)  London 


Berlin 


Urban  American  (white) 


New  York 


1680 

50.0 

1780 

40.0 

1905 

15.1 

1751  to  1780 

39.34 

1841  to  1870 

28.78 

1871  to  1900 

26.22 

1804  to  1825 

24.6 

1826  to  1850 

25.7 

1864  to  1875 

25.4 

1876  to  1888 

22.9 

1889  to  1901 

21.0 

1901  to  1909 

UA 

(1886 

25.99 

\   1908 

16.52 

11917 

13.78 

20  INTRODUCTION 

(c)  Only  a  few  figures  may  be  cited  as  proof  of  the  consid- 
erable decrease  of  mortality  from  certain  preventable  diseases : 

Typhoid  Fever  Mortality  Reduced  per  100,000. 

Hamburg  from    39.7  in  1880-92   to     7.2  in  1894-99 

Munich  from  291.0  in  1856  to    10.0  in  1887 

Lawrence,  Mass.  from  105.0  in  1892         to  22.0  in  1896 

Smallpox  Mortality  Reduced  per  100,000. 
Prussia  from    24.4  in  1846-70   to      1.5  in  1875-86 

Yellow  Fever  Mortality  Reduced  per  100,000. 
Havana  from  300.5  in  1870         to        .0  in  1901 

>,-.  rY-e^^-'- 
The  disease  of  mortality  from  other  diseases,  like  malaria, 
typhus,  cholera,  plague,  etc.,  is  shown  by  statistical  data  from 
various  countries  and  for  similar  periods. 

Further  Possible  Prevention  of  Disease.— According  to  the 
calculations  of  Professor  Fisher,  "the  length  of  life  could 
easily  be  increased  from  forty-five  to  sixty  years,  an  elon- 
gation of  fifteen  years.  This  would  result  in  a  permanent 
reduction  in  the  death  rate  of  about  25  per  cent.  The  prin- 
cipal reductions  would  come  from  the  prevention  of  infantile 
diarrhea  and  enteritis  (over  60  per  cent.),  bronchopneumonia 
(50  per  cent.),  meningitis  (70  per  cent.),  typhoid  fever  (85  per 
cent.),  tuberculosis  (75  per  cent.),  deaths  by  violence  (35  per 
cent.),  pneumonia  (45  per  cent.),  so  that  the  estimate  of 
fifteen  years  as  prolongation  of  life  is  a  safe  minimum  without 
taking  into  account  possible  future  discoveries  in  medicine 
or  the  cumulative  influence  of  hygiene." 

Economic  Value  of  Human  Life. — National  health  being  the 
greatest  national  asset,  it  has  been  sought  to  calculate  the 
economic  -value  of  human  life  and  the  financial  loss  through 
preventable  deaths  and  diseases. 

According  to  Fisher,  "the  average  value  of  a  person  now 
living  in  the  United  States  is  $2900,  and  the  average  loss  of  a 
life  sacrificed  by  preventable  disease  is  $1700.  As  the  num- 
ber of  preventable  deaths  is  calculated  to  be  about  630,000, 
the  financial  annual  loss  is  630,000  times  $1700,  or  over 
$1,000,000,000." 


ECONOMIC  VALUE  OF  HUMAN  LIFE  21 

Professor  Fisher  also  calculates  "that  there  are  always 
about  3,000,000  persons  in  the  United  States  on  the  sick 
list,  of  whom  1,000,000  are  in  the  working  periods  of  life, 
three-quarters  of  whom  are  actually  workers  and  must  lose 
at  least  $700  each  annually,  which  makes  a  further  loss  of 
about  $500,000,000,  to  which  may  be  added  $500,000,000 
spent  for  medical  attendance,  drugs,  etc.,  making  a  total  loss 
of  $1,000,000,000,  about  one-half  of  which  is  preventable; 
hence,  the  total  loss  by  deaths  and  disease  which  are  pre- 
ventable amount  to  about  $1,500,000,000  annually.'* 


QUESTIONS. 

What  is  hygiene? 

Give  definitions  of  public  hygiene,  personal  hygiene. 
Define  sanitary  science,  art,  sanitation,  sanitary  law 
What  are  the  aim  and  functions  of  hygiene? 

What  are  the  aim  and  functions  of  public  and  personal  hygiene? 
State  the  scope  and  function  of  sanitary  science. 
Give  example  of  ancient  sanitary  legislation. 
State  some  of  the  ancient  sanitary  undertakings. 
Since  when  do  we  date  the  progress  of  sanitary  science? 
In  what  does  sanitary  progress  manifest  itself? 
Has  the  span  of  human  life  been  lengthened?    How  much? 
Has  mortality  rate  been  decreased?    Give  examples. 

Has  morbidity  from  special  diseases  been  reduced?    In  what  diseases  and 
to  what  extent? 

Wliat  are  the  further  possibilities  in  disease  prevention? 
What  is  the  economic  value  of  human  life? 


CHAPTER  II. 
HOUSING  HYGIENE. 

Housing  hygiene  deals  with  the  subjects  of  the  relation  of 
housing  to  health,  and  of  the  prevention  of  disease  and 
promotion  of  health  by  improved  construction,  arrangement, 
and  maintenance  of  human  habitations. 

Housing  and  Health. — ^A  large  part  of  human  life  is  spent 
within  doors,  in  houses,  and  any  adverse  conditions  of  housing 
will  injuriously  affect  the  health  of  the  house-dwellers. 
Housing  conditions  are  therefore  important  environmental 
factors  influencing  life  and  health. 

The  dangers  to  individual  health  from  housing  depend  on  the 
defects  in  construction,  lighting,  ventilation,  heating,  drain- 
age, plumbing,  and  maintenance  of  the  house. 

The  influence  of  housing  on  public  health  depends  on  the 
location  of  the  houses  in  urban  or  rural  localities,  on  the 
density  and  overcrowding  of  areas  and  houses,  and  on  the 
sanitary  regulation  and  supervision  of  housing  construction 
and  conditions  by  the  community. 

BUILDING  MATERIALS. 

The  materials  used  for  house  construction  vary  according 
to  climate,  geographical  location,  and  physical  character  of 
the  site.  Among  the  materials  used  are  wood,  natural  stone, 
artificial  stone,  brick,  concrete,  iron,  and  other  metals. 

Wood  is  the  most  extensively  used  material.  It  is  strong, 
durable,  easily  obtained  in  most  localities,  and  worked  with 
comparatively  little  difficulty. 

The  objections  against  wood  as  a  building  material  are  that 
it  is  very  absorbent,  that  it  is  inflammable,  that  it  shrinks, 
and  that  it  is  subject  to  the  actions  of  insects,  moulds,  and 

(22) 


BUILDING  MATERIALS  23 

fungi,  and  to  certain  diseases,  like  dry  rot,  etc.  As  most  of 
the  diseases  to  which  lumber  is  exposed  are  helped  by  damp- 
ness, wood  is  commonly  made  to  undergo  a  process  of 
"seasoning"  before  being  used  for  building  purposes,  or  it 
is  impregnated  with  certain  chemicals,  like  zinc  chloride, 
copper  sulphate,  creosote,  etc.,  to  "preser\-e"  it.  Many 
kinds  of  wood  are  used  for  building  purposes,  from  the 
native  soft  yellow  pine  to  the  exotic  woods,  like  ebony,  rose- 
wood, etc. 

Stone. — Natural  stone  is  Ihe  strongest,  most  durable,  and 
most  beautiful  material  for  house  construction.  The  stone 
used  varies  in  its  quality,  hardness,  appearance,  etc. 

Brick  is  a  semivitrified  moulded  clay,  the  quality  of  the 
brick  depending  on  the  chemical  composition  of  the  clay 
and  the  methods  of  its  manufacture. 

Brick  absorbs  considerable  quantities  of  water.  It  is  made 
in  various  shapes,  and  some  bricks  are  made  with  enamelled 
surfaces. 

Terra-cotta  is  made  of  certain  clays,  well  baked,  and  is 
shaped  in  various  forms  according  to  need.  It  is  a  good 
fireproof  or  fire-resisting  material,  and  is  also  used  for  orna- 
mentation. 

Limes  and  Cements. — Limes  and  cements  are  used  for  bind- 
ing stones,  bricks,  etc. 

Common  lime  is  a  product  of  the  calcination  of  nearly  pure 
carbonate  of  lime.  It  has  a  great  avidity  for  water,  evolving 
considerable  heat  during  the  process  of  absorption.  On 
exposure  to  air,  lime  hardens  by  absorbing  carbonic  acid  and 
forming  carbonate  of  lime.  Mixed  with  sand,  lime  forms 
mortar.  Hydraulic  lime  is  a  lime  which  hardens  under 
water,  owing  to  the  constituent  aluminates  and  silicates  in 
the  lime. 

Cements. — Portland  cement  is  produced  by  subjecting 
a  mixture  of  carbonate  of  lime  to  a  calcinating  process  in 
special  kilns  and  then  reducing  it  to  a  fine  powder. 

Portland  cement  is  slow  in  setting,  sets  under  water,  and 
when  mixed  with  sand  forms  a  strong  mortar  for  use  in  all 
masonry  work. 


24  HOUSING  HYGIENE 

Concrete  is  cement  mixed  in  certain  proportions  with  sand 
and  gravel,  or  small  stones. 

Natural  cement  (sometimes  also  called  Rosendale  or  New 
York)  is  made  of  natural  rock  containing  the  right  propor- 
tions of  clay  and  carbonate  of  lime;  the  rock  is  broken, 
crushed,  heated,  ground,  and  pulverized. 

Reinforced  concrete  is  a  concrete  into  which  during  the 
process  of  setting  are  embedded  metal  wires  or  bars,  etc.,  to 
add  strength. 

Other  materials  used  in  house  construction  are  the  various 
metals — iron,  steel,  tin,  brass,  zinc,  lead,  copper — and  the 
bitumens — asphalt,  pitch,  tar;  also  gypsum,  asbestos,  etc. 


FIRE  PROTECTION. 

Fire  protection  is  a  most  important  consideration  in  house 
construction  in  order  to  prevent  the  loss  of  property  and  life. 

There  are  three  methods  of  reducing  the  dangers  from  fires : 
fireproof  building  materials,  fireproof  methods  of  construction, 
and  appliances  for  escape  during  fires  and  for  extinguishing 
fires.  The  term  "fireproof"  is  misleading,  as  there  are  few 
materials  which  are  absolutely  fireproof  or  non-combustible. 
What  is  commonly  meant  by  the  term  is  a  material  more  or 
less  fire-resisting.  Among  the  important  fire-resisting  build- 
ing materials  are  the  following:  stone,  iron,  concrete,  burnt 
terra-cotta,  fire-clay,  asbestos,  mineral  wool.  The  first  three 
materials  are  but  ignition-proof,  but  cannot  resist  high  tem- 
peratures unless  covered  by  the  latter  materials. 

Fireproof  construction  consists  in  the  elimination  of  wood, 
'  continuous  air  shafts,  air  wells,  and  hollow  communications 
between  floors;  the  lining  of  all  such  absolutely  indispensable 
openings  with  fire-resisting  materials  and  providing  them 
with  metal  self-closing  doors;  the  construction  of  floors  and 
ceiling  of  reinforced  concrete  and  of  metal  columns  protected 
by  burnt  terra-cotta;  using  asbestos  or  mineral  wool  for 
filling  in  openings  in  walls,  floors  and  other  places,  etc. 

Fire  Extinguishers. — ^The  appHances  for  the  puttmg  out  of 


HOUSE  DAMPNESS  25 

fires  consist  in  automatic  water  sprinklers,  or  the  presence 
and  provision  of  chemical  fire-extinguishing  apparatus,  etc. 

Fire  Escapes. — The  appHances  for  the  speedy  escape  of 
dwellers  during  fires  consist  in  the  broadening  of  stairways, 
in  the  construction  of  fireproof  stairways,  in  the  provision 
of  ample  fire  escapes  made  of  iron,  with  suitable  balconies, 
ladders,  etc. 

HOUSE   DAMPNESS. 

House  Dampness  and  Health. — Dampness  of  houses,  i.  e., 
the  excessive  moisture  of  the  walls,  floors,  and  ceilings  of 
the  house,  and  consequent  increase  in  the  relative  humidity 
of  the  air  in  the  rooms,  is  very  prevalent  in  most  houses; 
mdeed,  there  are  few  houses  which  are  free  from  dampness. 

The  following  is  a  resume  of  the  probable  effects  of  damp- 
ness: 

Damp  houses  are  cold  houses,  damp  walls  are  cold  walls, 
because  damp  walls  and  moist  air  are  good  conductors  of 
heat. 

Individuals  lose  more  body  heat  in  damp  houses;  more  fuel 
is  needed  to  warm  such  houses. 

Damp  houses  favor  chilling  of  the  body  surfaces,  have  a 
depressing  effect  on  the  hiunan  organism,  and  decrease  its 
resisting  powers. 

Damp  houses  favor  development  of  moulds,  fungi,  dry 
rot  and  "  haus-schwamm"  in  wood,  efilorescence  and  salt- 
petering  in  masonry,  and  also  favor  insects  and  germ  life 
within  the  house. 

Damp  houses  cause  the  mildewing  of  clothes,  injm'e  fur- 
niture, produce  spots  on  walls,  make  house  cleaning  difficult, 
heating  expensive,  interfere  with  ventilation,  and  decrease 
the  suitability  of  the  house  as  to  comfort  and  shelter. 

Damp  houses  may  safely  be  regarded  as  predisposing  causes 
of  tuberculosis,  bronchitis,  pneumonia,  nephritis,  rheuma- 
tism, and  other  diseases. 

The  causes  of  dampness  in  houses  may  be  due  to  condi- 
tions existing  above  the  cellar,  or  to  those  in  and  under  the 
cellar, 


26  HOUSING  HYGIENE 

Dampness  in  houses  above  the  cellars  may  be  due  to  one  of 
the  following  causes: 

1.  Porosity  of  building  materials. 

2.  Water  coming  into  contact  with  the  walls  and  roof. 

3.  Defects  in  construction  and  maintenance,  such  as 
defects  in  roof,  leaders,  and  walls. 

4.  Occupation,  uses,  and  abuses  of  house:  the  presence  of 
persons,  the  heating  and  illumination,  with  the  consequent 
production  of  aqueous  vapor,  the  bathing,  washing,  and  the 
Uke. 

5.  Capillary  attraction  from  the  ground. 

Dampness  of  houses  in  or  under  the  cellars  is  due  to  the 
entrance  of  water  into  the  cellar  from  the  following  sources: 

1.  Surface  waters  from  adjoining  ground. 

2.  Subsoil  water  percolating  through  foundation. 

3.  Tidewater  through  ground  or  pipes. 

4.  Leaks  in  water  supply  service  pipes. 

5.  Leaks  in  plumbing  fixtures  or  pipes. 

Prevention  of  House  Dampness. — ^The  prevention  of  house 
dampness  is  best  accomplished  by  removal  of  the  causes  of 
the  dampness,  and  may  be  summed  up  as  follows  : 

1.  Selection  of  dry  and  well-drained  sites. 

2.  Use  of  dry  and  well-seasoned  building  materials. 

3.  Tliorough  drying  of  newly  constructed  houses  before 
occupation. 

4.  Careful  use  of  water  and  steam  within  house. 

5.  Prevention  of  artificial  sources  of  water  in  cellars. 

6.  Damp-proof  method  of  house  construction. 

There  are  three  principal  methods  of  damp-proof  construc- 
tion: 

1.  Isolation  by  damp-proof  courses. 

2.  Surface  coating  by  damp-proof  substances. 

3.  Incorporation  of  damp-proof  compounds  into  mate- 
rials. 

Isolation  by  Damp-proof  Courses. — The  isolation  of  the  build- 
ing horizontally  from  the  subsoil  or  vertically  from  the 
adjoining  ground  is  accomplished  by  inserting  In  the  founda- 
tions and  Into  the  walls  a  damp-proof  material.    Among  the 


BUILDING  CONSTRUCTION  27 

materials  used  for  such  damp-proof  courses  are  the  bitumens 
— asphalt  and  pitch— in  the  form  of  felt  and  papers  impreg- 
nated with  these  materials  and  laid  in  several  thicknesses 
coated  with  hot  pitch.  Other  materials  used  for  damp-proof 
courses  are  glass,  slate,  lead,  etc. 

As  a  damp-proof  course  for  external  walls  some  advocate 
the  interposition  of  air,  which,  being  a  bad  conductor,  pre- 
vents the  ingress  of  moisture  into  the  inner  wall;  hence,  the 
construction  of  hollow  or  double  walls  bound  with  non- 
absorbent  ties  or  bonds.  The  objections  to  hollow  walls  are 
that  they  weaken  the  structure,  and  that  the  absorption  and 
condensation  of  moisture  instead  of  assisting  dryness  tends 
to  keep  the  inner  wall  damp. 

The  surface-coating  methods  of  waterproofing  consist  in 
the  external  application  of  waterproof  paints,  varnishes, 
asphalt  cements,  liquid  bitumen  compounds,  etc.,  to  the 
external  walls,  thus  preventing  the  ingress  of  moisture  through 
walls.  A  method  known  as  "Silvester's"  consists  in  washing 
off  masonry  walls  with  a  solution  of  castile  soap,  then  coating 
the  wall  with  a  solution  of  alum,  which  upon  drying  forms 
a  water-repellant  coating. 

The  third  method  of  damp-proofing  consists  in  the  incor- 
poration in  the  building  materials,  especially  mortars,  cement 
and  brick,  of  certain  waterproof  materials,  mostly  of  the 
bitumen  class. 

BUILDING  CONSTRUCTION. 

Aspect,  Soil,  and  Site. — ^The  importance  of  the  site  of  the 
house  cannot  be  overestimated,  as  on  the  site  and  its  proper 
selection  depend  whether  the  house  shall  be  dry  or  damp, 
cold  or  warm,  etc. 

The  aspect  of  the  house  with  relation  to  wind  and  sun  is 
important  in  relation  to  insolation  and  dr^mess  of  the  house. 

The  relation  of  the  soil  to  health  has-been  claimed  by  older 
hygienists  to  be  of  great  importance,  and  it  w^as  believed  that 
the  character  of  the  soil  bears  a  direct  relation  to  the  incidence 
of  cholera,  typhoid  fever,  tuberculosis,  etc.   WTiile  such  claims 


28  HOUSING  HYGIENE 

may  be  regarded  as  exaggerated,  it  is  nevertheless  conceded 
that  the  character  of  the  soil,  its  chemical  composition,  its 
hardness,  the  depth  of  the  ground-water  level,  the  fluctuation 
of  said  level,  etc.,  play  important  roles  in  the  sanitation  of  the 
house,  and  that  the  dryness,  warmth,  and  comfort  of  a  house 
depend  on  the  kind  of  soil  upon  which  it  is  situated. 

When  sites  are  water-logged,  or  when  the  ground-water 
level  is  above  the  height  of  the  foundations,  the  water  may  be 
drained  away  by  means  of  porous  unglazed  clay  pipes  in  the 
subsoil,  placed  with  a  pitch  toward  a  nearby  watercourse, 
thus  draining  away  the  excess  of  water. 

Foundations,  Footings,  and  Cellars. — ^The  foundation  is  the 
surface,  or  bed,  on  which  the  whole  house  rests ;  its  preparation 
and  proper  treatment  are  of  the  utmost  importance. 

The  preparation  of  a  foundation  bed  is  not  difficult  in  clay  or 
firm  earth.  An  excavation,  somewhat  larger  than  the  size  of 
the  house,  is  made,  the  loose  soil  removed,  the  place  levelled, 
and  the  level  surface  covered  with  several  inches  of  concrete, 
upon  which  surface  the  house  then  is  constructed. 

When  the  site  is  rocky  the  rock  must  be  cleared  away  by 
blasting,  and  the  foundation  bed  may  then  be  prepared 
without  a  layer  of  concrete. 

When  the  soil  is  water-logged,  marshy,  or  consists  of  quick- 
sand, or  is  entirely  under  water,  the  preparation  of  foun- 
dation is  a  difficult  matter,  as  it  is  then  necessary  to  resort  to 
the  creation  of  an  artificial  foundation  bed,  which  is  accom- 
plished by  several  methods,  either  by  driving  wooden  piles 
into  the  soil,  sawing  off  their  tops  and  constructing  the  founda- 
tion upon  these  piles,  or  by  sinking  caissons,  cofferdams,  etc. 

Once  the  foundation  is  prepared,  the  footings,  or  base- 
courses  of  the  walls,  are  to  be  constructed  of  stone,  or  of 
concrete,  to  a  thickness  somewhat  greater  than  that  of  the 
superimposing  wall,  and  of  a  strength  sufficient  to  bear  the 
weights  to  be  superimposed  upon  them. 

A  cellar  is  the  lowermost  story  of  the  house,  and  must  be 
well  constructed,  especially  in  regard  to  insolation  of  floor 
and  walls  from  the  adjoining  ground  by  damp-proof  courses 
in  order  to  prevent  the  appearance  of  water  in  the  cellar  or 


BUILDING  CONSTRUCTION  29 

dampness  in  the  walls.  Dry  areas,  several  feet  in  width, 
around  the  cellar  are  necessary  to  insure  dryness  and  light. 
Cellars  must  be  at  least  eight  feet  high,  should  not  be  used 
for  living  purposes,  and  should  be  provided  with  ample  win- 
dows and  means  of  ventilation  and  warming,  as  the  air  from 
the  cellar  is  being  constantly  drawn  up  into  the  rest  of  the 
house,  and  the  air  of  the  house  will  not  be  better  than  that 
of  the  cellar. 

Walls,  Floors,  Roof,  etc. — ^The  methods  of  wall-construc- 
tion depend  on  the  material  of  which  the  walls  are  made. 
In  frame  construction  the  security  of  the  wall  depends  on  the 
timber-posts,  sill,  and  plate,  while  in  masonry  construction 
the  walls  are  made  of  stones  joined  by  cement  mortar,  or  of 
brick  set  in  lime  or  cement  mortar.  In  concrete  construction 
the  walls  are  made  either  of  moulded  blocks  of  concrete  set 
in  cement  mortar,  or  of  soft  concrete  poured  into  moulds 
and  left  to  set  and  harden.  Walls  may  also  be  made  of  con- 
crete reinforced  by  steel  rods,  etc.,  embedded  in  the  concrete, 
or  the  walls  may  be  made  of  steel  columns  riveted  together 
and  covered  with  cement  or  terra-cotta. 

The  sanitary  demands  of  floor  construction  are  that  thef 
floors  must  be  secure,  and  proof  against  air,  dust,  sound, ' 
heat,  vermin,  fire,  and  water.  Unfortunately,  floors  rarely 
fulfil  all  these  sanitary  demands.  The  ordinary  floors  in 
houses  are  made  of  stout  timbers,  called  joists,  placed  upon 
edge  at  a  fixed  distance  one  from  another,  the  upper  surface 
of  which  is  covered  with  wide  boards  nailed  upon  them,  while 
the  under  surface  is  furred,  lathed,  and  plastered,  and  forms 
the  ceiling  of  the  lower  room.  As  the  space  between  the 
floor  and  ceiling  is  empty,  the  floor  becomes  a  very  good 
conductor  of  air,  dust,  heat,  and  sound,  greatly  assisting  the 
spread  of  fire. 

Modem  floor  construction  demands  that  the  floors  be  either 
solid,  of  reinforced  concrete,  or  that  the  space  within  them 
be  filled  with  mineral  wool,  asbestos,  or  that  the  floor  be 
made  of  steel  beams  encased  in  terra-cotta,  with  interspaces 
of  reinforced  concrete. 

Roofs  must  be  dust,  sound,  heat,  fire,  and  waterproof.    The  ^1 


30  HOUSING  HYGIENE 

materials  of  which  roofs  are  made  are  straw,  thatch,  wood 
shingles,  slate,  tile,  brick,  glass,  tin,  iron,  lead,  tar,  composi- 
tion materials,  etc.  An  air  space  between  the  roof  and  ceiling 
of  the  uppermost  floor  is  necessary  as  a  preventive  against 
too  rapid  conduction  of  heat,  etc. 

HOUSE-PLAN  AND  ARRANGEMENT. 

General  House-plan  and  Arrangement. — ^Theoretically,  every 
dwelling  should  be  planned  and  arranged  for  the  particular 
needs  of  the  family  which  is  to  occupy  the  same.  In  practice 
such  is  seldom  the  case,  and  the  house  dwellers  must  adjust 
themselves  to  the  already  constructed  house. 

Special  rooms  are  constructed  for  the  special  functions 
carried  on  within  the  house,  such  as  cooking,  sleeping,  eating, 
entertaining,  etc.,  as  well  as  special  rooms  for  each  member 
of  the  family,  especially  for  sleeping  purposes. 

In  internal  construction  the  partitions  and  inner  walls  are  of 
importance,  and  the  ordinary  construction  of  the  same  of  light 
timbers,  with  furring,  lathing,  and  plastering,  is  reprehensible, 
as  it  renders  them  extremely  combustible,  and  neither  sound 
nor  damp-proof.  The  substitution  of  metal  framing  and 
metal  lathing  is  very  desirable  for  partition  construction  as  for 
external  walls. 

The  construction  of  halls,  stairways,  and  the  internal  decora- 
tions of  walls  and  other  parts  of  construction  of  the  inner 
house  are,  of  course,  of  the  utmost  importance.  Stairways 
should  be  invariably  of  fire-resisting  material,  should  be  not 
too  steep,  with  frequent  changes  in  direction,  and  a  rise  of 
not  more  than  six  inches. 

In  modern  construction  the  sharp  corners  and  angles 
formed  by  ceiling  and  wall  and  wall  and  floor  are  eliminated 
by  a  rounding-up  of  these  surfaces. 

As  a  rule,  the  smoother  the  inner  surfaces,  and  the  less 
mouldings,  projections,  carving,  and  rough  spaces  within  the 
house,  the  better.  Inner  walls  should  be  so  treated  as  to 
make  them  readily  washable;  therefore,  papering  walls  and 
ceilings  is  objectionable,  also  because  of  the  arsenical  pig- 


LIGHTING  31 

merits  so  frequently  found  in  them,  and  because  of  the 
fouling  of  the  flour  paste  with  which  they  are  made  to  adhere 
to  the  wall.  Some  modern  papers  are  made  of  composition, 
and  are  readily  washable.  Floors  should  be  preferably  of 
hard  wood,  or  of  tiling  or  cement.  Kitchens,  baths,  and 
laundry  rooms  should  have  all  surfaces  hard  and  smooth, 
and  damp-proof. 

LIGHTING. 

Natural  Light. — Sunlight  is  essential  for  the  growth  of 
animal  and  vegetable  life;  it  acts  beneficially  upon  health, 
stimulates  the  metabolism  of  the  body,  assists  in  the  oxygen- 
ation of  the  blood.  Sunlight  is  also  a  powerful  germicide 
and  disinfectant;  it  kills  low  organisms,  fungi,  and  moulds, 
is  capable  of  destroying  tubercle  bacilli  within  a  short  time, 
and  is  therefore  indispensable  in  human  habitations.  Habi- 
tations without  direct  sunlight  are  damp,  cold,  and  unhealthy. 

The  amount  of  natural  light  within  a  house  depends  on: 

1.  Location  and  aspect  of   the  house. 

2.  Sources  of  light. 

3.  Location  and  size  of  openings  through  which  it  pene- 
trates. 

4.  Character  of  windows  and  of  surfaces  within  the  house. 
Direct  rays  of  the  sun  give  more  light  than  the  reflected 

lights  from  adjacent  surfaces,  walls,  trees,  etc. 

Greater  light  is  obtained  through  horizontal  openings  on 
top  of  the  house  than  from  windows  in  vertical  walls. 

The  intensity  of  light  within  a  house  depends  on  the  char- 
acter of  the  window  glass,  as  there  is  a  loss  of  light  of  50  per 
cent,  through  milk  glass,  10  per  cent,  through  double  glass, 
and  8  per  cent,  through  plate  glass.  Prism  or  ribbed  glass, 
by  distributing  and  reflecting  the  rays  of  the  light  evenly 
through  the  room,  increase  its  amount. 

The  window  area  of  a  room  should  not  be  less  than  10  per 
cent,  of  the  floor  area;  one  square  foot  of  glass  surface  thould 
be  allowed  for  every  70  cubic  feet  of  interior  space  to  be 
lighted.    Piers  between  windows  should  be  narrow;  window 


32  HOUSING  HYGIENE 

tops  should  extend  to  the  ceiHng,  at  least  within  six  inches 
from  same.  Plate  glass  is  best  for  transmission  of  light, 
unless  prism  glass  is  used.  Smooth,  light,  or  white  colored 
surfaces  of  inner  walls  and  floor  and  ceilings  increase 
amount  of  reflected  light. 

Artificial  illumination  in  the  house  is  obtained  by  the  rais- 
ing of  certain  substances  containing  carbon  to  a  degree  of 
incandescence.  Artificial  illumination  is  obtained  from 
electricity,  or  from  oils,  alcohols,  water  gas,  coal  gas,  and 
acetylene  gas. 

The  value  of  artificial  illumination  is  judged  by  the  following 
characteristics:  intensity,  quality,  heat  production,  amount 
of  impurities,  safety,  and  cost. 

Electric  light  may  be  very  intense;  ordinary  incandes- 
cent bulbs  are  of  16  to  32  candle  power;  the  Tungsten  lights 
give  a  more  intense  light  at  less  cost. 

Acetylene  gas  may  give  a  very  intense  and  brilliant  light 
of  from  20  to  160  candle  power,  while  the  intensity  of  other 
lights  depends  on  their  material,  character  of  burners,  etc. 
Welsbach  lights  are  made  of  mantles  impregnated  with 
earthy  silicates,  which  become  incandescent  upon  slight  heat- 
ing, giving  from  60  to  120  candle  power. 

All  illuminants,  except  electricity,  produce  much  heat  and 
give  off  some  impurities,  such  as  CO,  CO2,  sulphur  com- 
pounds, ammonia  compounds,  smoke,   soot  and  moisture. 

Acetylene  gas  (C2H2)  is  produced  by  mixing  water  with 
calcium  carbide,  during  which  process  much  heat  is  evolved. 
Special  generators  are  manufactured  for  the  production  of 
the  gas,  and,  contrary  to  the  current  opinion,  there  is  little 
danger  from  explosions,  as  calcium  carbide  is  not  explosive 
either  by  heat  or  by  concussion.  The  pipes  used  for 
ordinary  gas  illumination  may  also  be  used  for  acetylene 
lights,  except  that  the  tips  of  the  burners  must  be  smaller. 
The  light  is  intense,  steady,  white,  and  cheap,  and  is  very 
appropriate  for  houses  in  rural  communities,  or  wherever 
there  are  no  central  plants  for  the  manufacture  of  electricity 
or  coal  gas. 

Coal  gas  is  made  by  heating  bituminous  coal  in  air-tight 


AIR  33 

vessels,  during  which  process  the  combination  of  hydrogen 
and  carbon  are  transformed  into  other  gaseous  and  solid 
compounds.  The  refined  products  contain  about  50  per 
cent,  of  hydrogen,  35  per  cent,  of  marsh  gas,  6  per  cent,  of 
CO,  and  residue. 

Water  gas  is  manufactured  from  anthracite  coal,  steam, 
and  petroleum  by  a  complicated  process,  the  refined  product 
containing  30  per  cent,  of  CO,  35  per  cent,  of  hydrogen,  20 
per  cent,  marsh  gas,  and  residue. 

Because  of  the  increased  amount  of  CO,  water  gas  is  more 
dangerous  to  life  and  health  than  coal  gas.  The  inhalation 
of  even  small  amounts  of  water  gas  is  injurious,  wh41e 
large  amounts  may  become  fatal  by  the  carbon  monoxide 
combining  with  the  hemoglobin  of  the  blood  and  forming  an 
insoluble  compound. 

Coal  gas  and  water  gas  are  manufactured  in  central ', 
plants,  from  which  they  are  conducted  through  iron  tubes  -" 
and  pipes  under  the  streets  into  the  houses,  and  through  a 
network  of  smaller  iron  pipes  throughout  the  houses.  The 
gas-service  pipes  are  made  of  best  wrought  iron  with  malle- 
able iron  fittings,  and  the  house-service  should  be  provided 
with  main  and  secondary  stopcocks,  and  meters  to  measure 
the  amount  of  gas  consumed. 

The  gas-service  system  must  be  perfectly  air-tight,  should 
be  exposed  and  readily  accessible,  and  should  be  tested  for 
air-tightness  by  appropriate  tests  before  use. 

Gas  fixtures  are  of  various  shapes  and  value.  The  inten- 
sity of  illumination  greatly  depends  on  the  character  of  the 
burner.     Argand  and  Welsbach  burners  are  the  best. 

A  too  great  intensity  of  light  is  controlled  by  shades  and 
globes. 

AIR. 

The  atmospheric  air  surrounding  the  earth  is  quite  uniform 
in  its  composition.  It  contains  oxygen,  20.94 ;  nitrogen,  78.09 ; 
argon,  0.94;  carbon  dioxide,  0.03;  with  traces  of  hehum, 
kryton,  neon,  xenon,  and  hydrogen  (Haldane). 

The  most  important  of  the  constituents  of,  air  is  oxygen, 


■34  HOUSING  HYGIENE 

which  is  indispensable  to  combustion  and  breathing.  The 
function  of  nitrogen,  besides  that  of  a  diluent,  seems  to  be  to 
support  certain  forms  of  plant  life;  the  use  of  argon  is  un- 
known; carbon  dioxide  is  necessary  to  vegetable  life,  wherein 
the  carbon  is  used  for  the  carbohydrates.  Air  also  contains  a 
larger  or  smaller  percentage  of  moisture,-  and  near  the  earth's 
surface  it  contains  particles  of  dust  and  other  impurities. 

In  densely  populated  towns  the  composition  of  air  varies 
somewhat  from  the  standard,  in  that  the  carbon  dioxide 
may  reach  0.04  or  even  0.05  per  cent.,  the  amount  of  oxygen 
may  be  reduced  to  20.87,  while  the  number  and  quantities  of 
various  impurities  may  be  very  large,  consisting,  as  they  do, 
of  the  detrita  of  inorganic  and  organic  life  and  products  of 
combustion.  But,  whether  in  country  or  town,  the  natural 
constant  diffusion  of  the  air,  its  constant  motion  due  to  winds, 
currents,  and  variations  in  pressure  due  to  variations  in  tem- 
peratures, cause  such  a  thorough  mixing  of  the  air  that  its 
approximate  composition  remains  almost  always  constant, 
while  the  action  of  plants,  producing  oxygen  and  consuming 
carbon  dioxide,  equalizes  the  percentage  of  these  two  most 
important  constituents. 

House  Air. — "Wlien,  however,  the  air  is  shut  up  by  walls, 
ceiling,  and  floor  within  houses,  its  composition  naturally 
becomes  different  from  the  composition  of  external  air, 
having  become  contaminated  by  the  various  impurities 
manufactured  within  the  house. 

The  sources  of  the  impurities  in  au"  are  the  following:  (1) 
Respiration  of  persons;  (2)  illumination  and  heating;  (3) 
accidental  sources. 

The  expired  air  from  persons  differs  in  its  composition  from 
ordinary  air  by  a  decrease  of  oxygen  (4  per  cent.),  increase 
of  carbon  dioxide  (3.5  per  cent.),  and  an  excess  of  about 
5  per  cent,  of  aqueous  vapor.  There  is  also  an  increase  in 
the  temperature  of  the  air,  addition  of  some  volatile  matter, 
and,  occasionally,  some  bacteria  lodging  in  the  nose,  mouth, 
and  throat  may  be  dislodged  and  added  to  the  expired  air. 

Artificial  illumination  and  heating  decrease  the  amount  of 
oxygen,  increase  the  amount  of  carbon  dioxide,  raise  the  tern- 


AIR  35 

perature,  add  to  the  amount  of  aqueous  vapors,  and  may 
also  add  products  of  faulty  combustion — carbon  dioxide, 
carbon  monoxide,  sulphur  and  ammonia  compounds,  etc. 

Accidental  Sources  of  Air  Impurities.^ — Particles  of  inorganic 
and  organic  detrita,  dust,  etc.,  may  also  be  added  to  the  air 
from  accidental  causes,  such  as  walls  and  surfaces  of  the 
house,  processes  carried  on  within  the  same,  etc. 

Atmospheric  Pressure. — ^The  air  has  certain  weight  and  the 
atmosphere  exerts  a  certain  pressure.  This  pressure  is  con- 
siderable and  varies  according  to  altitude  and  temperature. 
Ordinarily,  it  is  unnoticed  by  us  as  the  pressure  is  equalized 
by  the  internal  pressures  of  our  bodies  adapting  themselves 
to  the  variations  in  the  pressure.  Changes  in  atmospheric 
pressure  are  measured  by  the  barometer.  Changes  in  atmos- 
pheric pressure  become  important  only  when  they  are  very 
marked.  Thus  in  high  altitudes,  the  air  may  be  so  rarified  as 
to  produce  what  is  called  "mountain  sickness,"  the  symptoms 
of  which  are  rapid  cardiac  action,  rapid  expiration,  headaches, 
etc.  More  grave  are  the  consequence  of  a  sojourn  in  an  atmos- 
phere at  a  greater  than  the  ordinary  pressure  such  as  must 
be  breathed  by  workers  in  tunnels,  caissons  and  by  divers. 

Humidity. — ^The  air  contains  moisture  or  watery  vapor  at 
all  times.  The  amount  of  the  watery  vapor  depends  upon  a 
great  many  factors.  At  times  the  air  may  be  saturated  with 
moisture.  When  air  is  saturated  with  moisture,  that  is,  when 
it  contains  all  the  water  it  can  absorb,  the  excess  of  moisture 
is  deposited  in  the  form  of  dew;  it  has  reached  then  what  is 
known  as  the  "dew  point."  The  utmost  amount  of  moisture 
which  air  may  contain  without  reaching  the  dew  point  is 
called  absolute  humidity.  The  difference  in  the  amount  of 
moisture  which  air  at  a  given  temperature  may  actually 
contain,  and  that  which  it  must  contain  in  order  to  reach 
absolute  saturation,  is  called  relative  humidity. 

Relation  of  Impurities  to  Health. — ^The  increase  of  carbon 
dioxide  becomes  of  importance  only  when  it  reaches  the 
mfrequent  amount  of  4  per  cent.,  provided  this  increase  in 
the  volume  of  the  carbon  dioxide  is  at  the  expense  of  oxygen; 
at  18  per  cent,  of  carbon  dioxide  in  the  composition  of  air, 


36  HOUSING  HYGIENE     . 

with  a  corresponding  reduction  in  volume  of  oxygen,  death 
may  follow  rapidly.  An  extreme  increase  of  carbon  dioxide 
without  a  corresponding  decreage  in  amount  of  oxygen  is 
seldom  taking  place. 

According  to  Rubner,  the  effects  of  the  air  of  inhabited 
rooms  are  due  to  certain  volatile  carbon  materials  which 
have  a  biological  influence  upon  health;  according  to  others 
lit  is  due  to  the  presence  of  expired  "fatigue  toxins;"  while 
Fliigge  claims  that  it  is  due  to  the  increased  temperature  of 
expired  air.  It  is  probable  that  the  ill-smelling  emanations 
from  persons  combined  with  the  increase  of  carbon  dioxide, 
decrease  of  oxygen,  increase  of  temperature  and  aqueous 
vapor,  all  play  a  certain  role  in  the  bad  effects  of  expired 
air  upon  human  beings. 

The  dust  in  the  air  of  rooms  may  be  considerable  and  ax^t 
as  a  mechanical  irritant. 

The  number  of  bacteria  in  the  air  may  be  considerable,  and 
some  pathogenic  microorganisms  may  adhere  to  the  dust  in 
the  air. 

The  work  of  later  sanitarians  tends  to  prove  that  the 
deleterious  effects  of  confined  room  air  are  mostly,  if  not 
entirely,  due  to  increased  temperature,  increased  humidity, 
and,  in  part,  to  air  stagnation. 

VENTILATION. 

Definition. — It  is  evident  that  with  a  number  of  persons 
present,  and  with  illumination,  combustion  and  other  pro- 
cesses being  carried  on  in  a  room,  the  added  impurities  in 
the  air  may  soon  reach  such  an  amount  that  breathing  may 
become  difficult  or  dangerous  on  account  of  the  added 
impurities.  Unless,  therefore,  there  is  an  influx  of  fresh  air 
from  the  outside  and  removal  of  the  impure  air,  the  room 
air  may  become  dangerous  to  health  and  life. 

Such  an  exchange  of  air,  the  removal  of  inside  impure  air 
and  its  substitution  by  fresh,  pure,  outside  air  is  called 
ventilation. 

The  amount  of  pure  air  needed  to  add  in  a  room  for  each 


VENTILATION  37 

average  person  has  been  estimated  as  3000  cubic  feet,  hence  / 
an  hermetically  closed  room  of  3000  cubic  feet  capacity, 
inhabited  by  one  average  person,  will  need  an  hourly  change 
of  air,  while  a  smaller  room  will  need  a  correspondingly  more 
frequent  change. 

Spontaneous  or  Natural  Ventilation. — Ventilation  is  carried 
on  in  ordinary  houses  spontaneously  through  the  natural 
diffusion  of  the  air  through  the  porous  walls  and  building 
materials  of  the  house,  or  the  openings,  cracks,  crevices,  etc;, 
usually  found  in  ordinary  constructed  houses. 

Natural  ventilation  is  also  the  exchange  of  air  facilitated 
by  making  artificial  openings  in  the  house  in  the  form  of 
windows,  transoms,  skylights,  or  special  openings  in  various 
places  within  the  house. 

Mechanical  ventilation  is  that  form  of  ventilation  which  is 
accomplished  by  a  forced  drawing  out  of  the  air  from  the 
house,  or  by  a  forced  introduction  of  outside  air  into  the 
house  by  mechanical  means. 

Not  much  dependence  may  be  placed  upon  spontaneous, 
natural  ventilation  carried  on  through  the  porous  building 
materials  and  accidental  openings.  With  a  great  difference  in 
the  temperature  of  external  and  internal  air  there  may  be 
a  certain  rate  in  the  exchange  of  air,  but  tnis  is  lessened  by  a 
more  tight  construction  of  the  house,  and  by  the  modern 
methods  of  painting  and  water-proofing  of  houses. 

The  principal  means  of  ventilation  in  most  houses  are 
the  windows,  doors,  and  the  artificial  openings  especially 
made  for  the  purpose. 

The  occasional  opening  of  doors  and  the  opening  of  win- 
dows greatly  assist  the  exchange  of  air  in  ordinary  dwellings 
with  not  too  many  persons  in  the  rooms  and  with  but  ordi- 
nary illumination  and  heating. 

When  the  number  of  persons  in  rooms  is  large  and  the 
number  of  lights  increased,  the  windows  and  doors  may  not 
be  sufficient  for  adequate  ventilation,  and  special  artificial 
openings  may  be  needed. 

The  number  and  character  of  such  openings  vary  in  size, 
location,  shape,  character,  etc. 


38  HOUSING  HYGIENE 

The  openings  may  be  in  the  shape  of  tubes  or  boxes  placed 
within  the  w-indows,  the  sashes,  the  panes,  the  wahs,  at  dif- 
ferent points,  the  ceihngs,  or  the  floors.  All  such  openings 
communicate  with  the  external  air,  and  serve  as  air  inlets, 
or  outlets,  and  may  also  be  provided  "s^'ith  adjustable  gates, 
so  that  they  may  be  closed  up  when  not  wanted. 

The  number  of  ventilating  devices  is  very  large;  their 
value  depends  on  their  location  and  size  and  character. 

'\^^le^e  local  heating  is  used  within  the  house,  ventilation 
is  aided  by  the  necessary  chimney  and  flue  openings,  and  by 
the  use  of  grates  and  stoves. 

Methods  of  Mechanical  Ventilation. — The  advantages  of 
mechanical  ventilation  are  the  constancy  of  the  exchange 
of  air,  the  independence  from  any  other  means,  the  perfect 
control  of  the  velocity  and  volume  of  the  supplied  air,  the 
possibility  to  accurately  regulate  the  temperature,  cjuantity, 
moisture,  and  purity  of  the  incoming  air. 

Mechanical  ventilation  is,  as  a  rule,  carried  on  from  a 
central  plant,  and  is  of  three  kinds — plenum,  or  propulsion 
method,  in  which  pure  air  is  driven  into  the  house  from 
outside;  vacuum,  or  exhaustion  method,  in  which  the  impure 
air  is  withdrawn  from  the  house;  and  the  combined  vacuum 
and  plenum  methods. 

Mechanical  ventilation  requires  motors  (steam,  water,  or 
electrical)  to  operate  the  propulsion  or  exliaust  fans,  etc.; 
central  ducts  and  tubes  which  radiate  throughout  the  build- 
ing, within  or  outside  of  walls,  floors,  etc.;  and  the  inlet  and 
outlet  boxes  or  openings  within  the  rooms. 

Incoming  air  mav  be  moistened,  cooled,  or  warmed,  and 
filtered  in  the  central  tubes;  its  velocity  may  be  measured  bj 
anemometers,  the  temperature  regulated  by  thermostats,  and 
humidity  controlled  by  humidostats. 


HEATING. 

"\Miile  the  human  body  may  be  accustomed  to  withstand 
great  variations  in  the  temperature  of  the  external  air,  the 


HEATING  39 

range  of  temperatures  of  the  air  within  houses  which  persons 
may  withstand  with  impunity  is  rather  Hmited. 

A  too  high  temperature  in  our  dwelHngs  interferes  with  the 
normal  heat  conduction  and  evaporation,  while  a  too  low 
temperature  is  dangerous  by  the  withdrawal  of  the  body 
heat  in  a  greater  rate  than  it  is  substituted. 

Sudden  changes  in  the  temperature  of  the  house  may  cause 
a  sudden  disturbance  in  the  heat  equilibrium  of  the  body, 
lower  the  resisting  forces  of  the  body,  and  predispose  to 
certain  diseases. 

The  proper  regulation  of  the  temperature  within  houses 
is  therefore  of  the  utmost  importance  to  health. 

The  proper  temperature  of  rooms  must  necessarily  vary 
according  to  many  factors,  such  as  the  season  of  the  year, 
character  of  houses,  strength  and  physical  condition  of  indi- 
viduals, habits,  activity,  etc. ;  but  allowing  for  all  the  differ- 
ences, it  may  safely  be  assumed  that  the  maximum  variations  of 
temperature  of  rooms  in  houses  for  the  average  house  dwellers 
should  be  in  winter  between  58°  and  70°  F.,  and  in  summer 
between  65°  and  75°  F.,  with  a  relative  humidity  of  40  to  50 
per  cent,  in  winter  and  50  to  60  per  cent,  in  summer. 

It  is  obvious  that  the  temperature  of  various  rooms  may 
somewhat  vary;  thus,  a  workroom  may  be  lower  in  temper- 
ature than  a  sickroom,  a  bedroom  lower  than  a  living  room, 
etc. 

The  hygienic  demands  on  a  system  of  heating  rooms 
are  as  follows:  Equable  temperature,  equable  distribution, 
continuous  heating,  absence  of  impurities,  proper  degree  of 
humidity,  freedom  from  danger  of  fires,  explosions,  etc.,  and 
relative  small  cost. 

Means  and  Methods  of  Heating. — Artificial  heating  of  houses 
is  accomplished  by  means  of  burning  certain  combustible 
materials  within  specially  constructed  receptacles. 

The  combustible  materials,  called  fuels,  are  the  following: 
Straw,  cornstalks,  dry  peat,  wood,  bituminous  coal,  anthracite, 
coke,  oil,  alcohol,  gas. 

In  the  ordinary  methods  of  combustion  the  various  waste 
matters  and  products  of  combustion  are  removed  through 
specially  made  flues  and  openings — the  chimneys. 


v{ 


40       •  HOUSING  HYGIENE 

The  quantity  of  waste  products  of  combustion  depends  on 
the  kind  of  fuel,  intensity  of  heat,  shape  and  character  of 
receptacles,  methods  of  heating,  etc. 

The  smoke,  gases,  and  other  impurities  of  combustion 
processes  may  be  lessened  by  improved  methods  of  com- 
bustion and  by  various  improved  devices,  like  smoke  con- 
sumers, etc. 

There  are  three  methods  of  heating — the  radiant,  the  con- 
ductive, and  the  convective.  The  heat  may  be  given  off  in 
direct  rays  from  the  combustible  materials,  as  in  grates,  or 
may  be  conducted  through  some  intermediate  material,  like 
iron,  tile,  etc.,  (stoves),  or  may  be  conveyed  by  means  of 
air,  water,  or  steam. 

Heating  may  also  be  local  or  central;  that  is,  the  heat  in 
rooms  may  be  derived  from  the  combustion  carried  on  in 
receptacles  in  each  room,  or  it  may  be  conducted  or  con- 
veyed from  a  central  location  within  or  outside  of  the  house. 

Local  Heating. — The  room  to  be  heated  contains  a  recep- 
tacle, or  stove,  in  which  the  combustible  material  is  placed, 
raising  the  temperature  of  the  stove  and  the  air  surrounding 
it,  and  thus  warming  the  room. 

Local  heating  is  accomplished  by  means  of  grates  and 
stoves.  Grates  are  the  oldest  form  of  heating,  and  are 
made  of  iron  or  tile  open  receptacles,  in  which  the  fuel  is 
placed,  which  on  combustion  gives  off  direct  rays  to  the 
surrounding  air  and  objects,  while  the  waste  products  are 
carried  off  through  the  chimney.  It  is  a  very  wasteful 
method  of  heating,  as  75  per  cent,  of  the  fuel  is  not  utilized  and 
is  lost,  the  heat  is  not  equally  distributed,  produces  draughts 
and  strong  currents,  and  cannot  adequately  warm  large  rooms 
all  over  equally.  Grate  stoves  greatly  assist  ventilation. 
The  Galton  form  of  grate  is  an  improvement  over  the 
ordinary  grate,  in  that  the  cold  air  from  the  outside  is  drawn 
into  the  grate,  where  it  is  warmed  and  returned  to  the  room 
over  a  special  opening,  thus  greatly  aiding  the  ventilation  of 
the  room. 

Stoves  are  made  of  iron,  tile,  brick,  etc.,  and  a  larger 
percentage  of  fuel  is  utilized  through  them,  as  their  heat  is 
not  only  radiant,  but  is  conducted  by  the  iron,  etc.,  of  which 


HEATING  41 

the  stoves  are  made.  Stoves,  however,  waste  a  great  deal 
of  the  fuel,  are  difficult  to  keep  up  continuously,  produce 
ashes  and  dirt,  necessitate  the  carrying  of  coal  and  fuel,  and 
are  otherwise  cumbersome  and  inconvenient.  When  red  hot, 
carbon  dioxide  and  other  gases  may  go  through  the  stove. 

Local  heating  by  means  of  illuminating  gas,  or  by  means 
of  electricity,  are  preferable  means  of  warming  rooms,  the  only 
objection  to  them  being  their  relatively  greater  cost. 

Central  Heating. — In  central  heating  the  combustion  takes 
place  not  in  the  rooms  to  be  warmed,  but  in  a  central  location, 
within  or  outside  of  the  house,  from  which  central  place  the  heat 
is  conveyed  by  means  of  special  pipes  and  flues  to  each  room. 

There  are  three  principal  systems  of  central  heating — air,  / 
water,  and  steam.  ' 

Hot-air  or  furnace  heating  is  very  popular  for  small  dwell-/ 
ings.  It  is  cheap  in  its  installation  ($75  to  $150  per  house); 
The  fuel  is  burned  in  a  cast-iron  combustion  chamber 
located  in  the  cellar;  the  combustion  chamber  is  surrounded 
by  an  iron  jacket  containing  air,  which  comes  thereto  from 
the  outside  through  a  cold-air  flue  or  box;  the  heated  air  in  the 
jacket  is  conducted  through  flues  and  pipes  throughout  the 
house,  the  pipes  ending  in  each  room  by  an  opening  called  a 
"register,"  which  may  be  opened  or  closed. 

The  advantages  of  hot-air  heating  are  its  simplicity  and 
relatively  small  cost,  while  there  are  a  number  of  grave  objec- 
tions to  it,  the  principal  ones  being  that  the  air  is  apt  to 
become  overheated  and  dry,  that  dust  and  smoke  may  gain 
entrance  through  registers  and  flues,  etc. 

Hot-water  Heating. — This  is  regarded  as  the  best  form  of  \ 
central  heating  for  small  dwellings.  Instead  of  an  air  jacket 
over  the  combustion  chamber,  there  is  provided  a  water 
receptacle,  from  which  a  continuous  pipe  ascends  through 
the  house  to  its  uppermost  part,  whence  it  returns  by  a 
continuous  descending  pipe  and  connects  with  same  water 
receptacle.  The  water  being  heated,  circulates  freely  through- 
out the  system  of  pipes  and  the  radiators  attached  thereto,  and 
by  the  heating  of  pipes  and  radiators  warms  the  air  of  the 
rooms.    Between  the  ascending  and  descending  pipes  there  is 


42  HOUSING  HYGIENE 

usually  placed  an  expansion  tank  to  allow  for  the  expansion 
of  the  water  by  heat. 

This  system  of  heating  is  simple,  needs  little  attention, 
produces  a  pleasant  and  not  too  high  temperature,  is  not 
subject  to  sudden  variations,  and  consumes  a  relatively  small 
amount  of  coal. 

Steam  Heating. — In  this  system  the  pipes  are  filled  with 
steam  instead  of  with  hot  water,  and  the  water  in  the  boiler 
is  converted  into  steam.  The  temperature  of  the  pipes  and 
radiators  is  higher,  their  size  correspondingly  smaller,  more 
fuel  is  needed  to  convert  the  water  into  steam,  a  higher 
pressure  gained,  more  expert  attention  necessary,  a  greater 
degree  as  well  as  variation  of  heat  reached.  This  system 
is  especially  suitable  to  large  houses.  Steam-heating  plants 
may  be  located  outside  of  the  house  and  convey  the  heat  by 
means  of  underground  steam  pipes. 


WATER  SUPPLY. 

Water  is  needed  for  drinking  purposes,  also  for  preparation 
of  food,  for  washing  the  body,  clothes,  etc. 

The  amount  of  water  needed  by  men  for  all  purposes  varies 
according  to  many  factors.  Fifty  gallons  per  day  is  a  safe 
average  minimum,  while  in  large  cities  and  civilized  com- 
munities a  supply  of  300  gallons  and  more  per  person  is  not 
excessive. 

Chemically  pm-e  water  consists  of  two  parts  of  hydrogen  and 
one  part  of  oxygen.  But  water  is  rarely  in  a  pure  state,  as 
it  is  a  very  great  solvent,  and  is  commonly  mixed  with  various 
foreign  ingredients,  some  of  which  are  harmless,  while  others 
may  be  deleterious.  Water  also  contains  gases  like  oxygen, 
carbonic  acid,  and  various  minerals. 

The  most  important  foreign  ingredients  in  water  are  those  of 
organic  origin,  such  as  microscopic  plants,  vegetable  fungi, 
detritus  of  vegetable  life,  minute  insects,  infusoria,  ova  of 
insects,  minute  parasites,  animal  debris,  products  of  organic 
decomposition,  etc.  The  ammonia,  nitrates,  and  nitrites 
frequently  found  in  water  are  commonly  due  to  results  of 


WATER  SUPPLY  43 

organic  decomposition.  Water  may  also  contain  metals  in  solu- 
tion, such  as  iron,  lead,  arsenic,  copper,  etc.  Water  usually 
contains  millions  of  various  microorganisms,  mostly  harm- 
less, although  at  times  it  may  also  contain  pathogenic  germs. 

"Hard"  and  "Soft"  Water. — Water  containing  carbonate 
of  lime  is  called  temporarily  hard,  the  carbonate  of  lime  being 
driven  o&  by  boiling;  when  water  contains  the  salts  of  mag- 
nesium, sulphates,  and  chlorides  it  is  called  permanently  hard, 
as  these  salts  are  not  removed  by  boiling.  A  water  without 
those  salts  is  called  "soft."  A  hard  water  precipitates  its 
salts  on  boiling,  prevents  the  softening  of  vegetables,  pre- 
vents the  formation  of  soap  lather,  hence  a  soft  water  is 
preferred  for  cooking  and  laundry  purposes. 

Good  water  should  be  clear,  free  from  sediment  and  sus- 
pended matter,  colorless,  odorless,  aerated,  cool,  soft,  and 
palatable.  Water  must  not  be  judged  by  one  quality,  and  cer- 
tainly not  by  its  palatability,  as  a  very  palatable  water  may  be 
contaminated  with  products  of  decomposition  and  owe  its 
taste  to  the  carbonic  acid  which  is  a  result  of  decompo- 
sition. 

Domestic  Water  Supply. — Water  is  derived  for  domestic 
supply  from  rain,  from  surface  collections,  and  from  springs 
and  wells. 

Rain  water  is  soft  and  pure,  unless  it  is  contaminated  by 
the  surface  air  or  by  the  receptacles  in  which  it  is  collected. 
It  is  not  palatable  until  it  is  well  aerated.  The  quantity  of 
rain  water  being  variable  and  inconstant,  no  absolute  reliance 
may  be  placed  upon  this  source  of  water  supply,  although  in 
rural  places  cisterns  and  tanks  are  commonly  provided  for  the 
catching  and  storing  of  rain  water. 

Surface  collections  of  water,  in  the  form  of  lakes,  ponds, 
and  rivers,  are  a  reliable  means  of  water  supply,  but  the  water 
being  exposed  to  contamination  of  organic  decomposition, 
surface  drainage,  and  sewage,  such  water  may  be  dangerous 
to  health. 

Subsoil  water  is  that  which  is  gained  from  wells  and^springs. 
Springs  are  the  outcroppings  of  d6e£_undergroun JwaterTanH 
are,  as  a  rule,  pure  and  free  from  impurities,  having  gone  great 
distances  through  the  ground  through  which  they  filtered. 


44  HOUSING  HYGIENE 

Shallow  wells  derive  their  water  from  surface  drainage 
and  the  falling  rain,  and  are  often  contaminated  by  sm-face 
sewage  and  products  of  organic  decomposition. 

Deep,  driven,  or  bored  wells,  deriving  their  water  from 
lower  subsoil  strata  of  underground  water,  are  free  from 
impurities,  provided  the  wells  are  properly  constructed, 
lined  with  non-absorbent  material,  are  well  covered,  and  are 
protected  from  surface  contamination. 

Domestic  Water  Purification. — Domestic  water  supply  may 
be  purified  by  sedimentation,  boiling,  distillation,  chemicals, 
or  by  filtration. 

By  sedimentation  it  is  possible  to  free  the  water  from  its 
mechanical  impurities,  sand,  dirt,  etc.,  without,  however, 
much  affecting  matters  held  in  solution. 

By  boiling,  all  organic  matter  and  germs  are  destroyed;  the 
taste  of  the  water  is,  however,  changed,  owing  to  expulsion 
of  gases. 

By  distillation  a  chemically  pure  water  is  gained,  which  may 
be  made  palatable  by  addition  of  carbonic  acid. 

By  the  addition  of  chemicals  to  suspicious  water — small 
doses  of  borax,  boracic  acid,  potassium  permanganate,  copper 
sulphate,  etc. — the  organic  matter  may  be  rendered  harmless; 
but  as  those  chemicals  are  not  a  desirable  addition  to  water, 
this  method  of  purification  is  objectionable. 

In  ordinary  households  the  boiling  of  waters  is  a  good  pre- 
caution whenever  the  water  supply  is  suspicious.  Distillation, 
provided  the  proper  apparatai'^re  at  hand  is  the  ideal  method. 

Water  may  be  purified  of  all,  or  nearly  all,  of  its  impurities 
by  filtration,  the  value  of  the  process  depending  upon  the 
medium  of  filtering,  the  efficiency  of  the  filter,  and  the  thor- 
oughness of  the  process. 

The  materials  used  for  filters  are  wool,  asbestos,  sand, 
stone,  porcelain,  infusorial  earth,  carbide  of  iron,  charcoal, 
etc. 

Infusorial  earth  pressed  in  the  form  of  hollow  tubes  are 
used  in  the  Berkefeld  filters,  which  are  efficient,  although 
needing  frequent  cleansing.  There  are  a  number  of  other 
filters,  quite  efficient,  provided  they  are  frequently  cleaned. 

Wliile  some  of  the  better  filters  may  remove  all  impurities, 


DRAINAGE  AND  PLUMBING  45 

even,  it  is  claimed,  all  bacteria,  from  the  water,  this  is  seldom 
the  case  with  filters  after  they  are  used  for  some  time. 

DRAINAGE  AND  PLUMBING. 

The  average  adult  excretes  daily  about  three  ounces  of 
solid  feces,  and  about  40  ounces  of  urine.  This  organic 
matter,  if  left  exposed,  soon  decomposes  and  putrefies,  and 
evolves  bad  odors.  The  excreta  may  also  contain  pathogenic 
germs  capable  of  causing  certain  diseases.  The  keeping, 
therefore,  of  excreta  within  houses  is  dangerous  to  health, 
and  its  immediate  disposal  a  sanitary  necessity. 

The  methods  of  immediate  disposal  of  excreta  may  Be  dry 
or  by  means  of  water.  The  dry  methods  are  by  means  of 
pails,  earth  closets,  and  privy  vaults;  where  there  is  a  water 
service  within  the  house  the  sewage  may  be  disposed  of 
through  a  system  of  pipes,  the  pipes  carrying  the  diluted 
sewage  outside  into  cesspool,  privy,  or  into  sewer. 

The  pail  system  is  the  simple  expedient  of  gathering  the 
sewage  into  water-tight  pails,  which  are  periodically  removed 
from  the  house  and  emptied  outside. 

Earth  closets  resemble  pails,  of  one  or  another  shape,  in 
which  the  excreta  is  mixed  with  earth,  and  the  mixture 
removed  with  the  closets,  or  through  a  system  of  wide  pipes. 

Privy  vaults  are  excavations  in  the  ground  outside  of  the 
house,  into  which  the  excreta  is  voided  and  where  it  is  left 
until  the  vault  is  full. 

The  objections  against  the  pail  and  earth-closet  systems 
are  in  the  care  they  demand,  the  difficulty  of  keeping  them 
clean,  the  need  of  frequent  emptying,  etc. 

The  objections  against  privy  vaults  are  their  proximity  to 
the  house,  the  putrefactive  changes  undergoing  in  them, 
evolving  gases  and  foul  odors,  the  dangers  of  flies  carrying 
infection  from  them  into  the  house,  and  the  greater  dangei 
of  contaminating  the  surface  ground  and  polluting  the 
sources  of  water  supply. 

The  water  carriage  disposal  of  sewage  consists  in  the  instal- 
lation of  plumbing  fixtures  and  pipes  within  the  house  from. 


46  HOUSING  HYGIENE 

which  the  sewage,  diluted  with  water,  is  sent  to  cesspools, 
fields,  or  sewers. 

A  cesspool  is  a  hole  in  the  ground,  similar  to  a  vault,  into 
which  the  liquid  sewage  and  other  liquids  from  the  house  are 
led  by  pipes  from  the  house.  It  should  be  at  some  dis- 
tance from  the  house,  should  be  constructed  water-tight, 
emptied  periodically,  or,  better,  be  provided  with  automati- 
ically  self-emptying  siphon  tanks  to  empty  its  contents  at 
certain  periods  over  the  adjoining  ground. 
/  Field  irrigation  may  be  employed  in  conjunction  with  a 
cesspool,  or  independently  of  same.  In  intermittent  irriga- 
tion the  flushing  tank  is  made  to  discharge  its  contents,  at 
certain  intervals,  into  a  system  of  underground  earthenware 
pipes,  with  open  joints,  the  pipes  being  laid  several  feet  under 
ground  and  radiating  in  various  directions.  The  liquid 
sewage  drains  into  the  ground  and  is  taken  care  of  by  the 
earth,  which  is  enriched  thereby.  Large  quantities  of  sewage 
may  be  disposed  of  with  advantage  upon  fields  by  such 
methods,  provided  care  is  taken  in  the  proper  installation  of 
the  flushing  tanks,  and  proper  periods  of  rest  are  given  to  the 
fields  to  dispose  of  the  organic  matter. 

House  Plumbing.— A  system  of  house-plumbing  consists 
essentially  of  three  parts — the  fixtures,  or  receptacles  into 
which  the  various  household  waste  is  dropped,  the  system  of 
pipes  leading  from  the  fixtures  throughout  the  house  outside, 
and  a  system  of  water  pipes  feeding  the  plumbing  fixtures 
and  diluting  the  waste  matter. 

The  fixtures  of  house  plumbing  are  variously  shaped  accord- 
ing to  their  functions,  and  range  from  kitchen  sink,  laundry 
tubs,  bath-tubs,  washbasins,  to  water  closets,  urinals,  etc. 
The  best  materials  for  making  these  fixtures  are  enamelled 
iron  and  porcelain,  although  cast  iron,  soapstone,  and  even 
wood  have  been  used  formerly. 

The  fixtures  are  connected  by  branches  to  the  several  verti- 
cal pipes  running  through  the  house,  each  serving  a  special 
function;  thus,  the  "rain  leader"  runs  outside  of  the  house 
and  collects  the  rain  from  the  roof;  the  "waste  pipe"  runs 
vertically  through  the  house  and  connects  with  all  kitchen 
sinks  and  laundry  tubs  or  washbasins,  while  the  "soil   pipe" 


DRAINING  AND  PLUMBING  47 

is  the  main  vertical  pipe  to  which  the  water  closets,  and  some- 
times the  bath  tubs  are  connected.  These  vertical  pipes 
run  through  the  house  and  join  in  the  cellar  to  the  horizontal 
and  inclined  main  pipe,  called  "house  drain,"  into  which  all 
the  various  waste  waters  and  sewage^fom  all  the  fixtures 
and  pipes  are  discharged.  The  house  drain  runs  through 
the  cellar  and  joins  the  street  sewer  by  a  short  connection 
called  "house  sewer,"  which  connects  the  house  drain  in 
front  of  the  house  with  the  sewer  jn  the  street. 

All  plumbing  pipes,  except  the  rain  leader,  which  may  be  of 
sheet  metal,  are  made  of  cast  iron,  with  lead-calked  joints. 
When  wrought-iron  pipes  are  used  they  are  connected  by 
screw  joints.  Short  branch  waste  pipes  may  be  of  lead 
connected  by  solder  wiped  joints,  but  when  connected  with 
iron  pipes  are  joined  by  means  of  brass  screw  ferrules,  or 
fittings,  calked  into  the  iron  and  soldered  to  the  lead. 

The  admission  of  "  sewer  air,'*  or  "  sewer  gas,"  as  it  is  called, 
is  prevented  by  means  of  the  so-called  "traps,"  which  are 
bends  in  the  pipes  so  constructed  as  to  hold  a  certain  amount 
of  water,  which  acts  as  a  barrier  and  prevents  the  foul  air 
from  the  sewer  side  of  the  traps  from  coming  into  the  house 
side  of  the  traps. 

In  modern  house  plumbing  there  is  usually  one  main  trap 
on  the  house  drain  near  the  front  wall  inside  of  the  house, 
this  trap  preventing  air  coming  from  the  street  sewer  into 
the  house,  and,  besides,  every  fixture  within  the  house  is 
separately  trapped  within  two  feet  from  the  fixture,  thus 
preventing  the  air  froin  the  pipes  from  entering  the  rooms 
through  the  fixtures. 

Seals  of  Traps. — ^The  traps  are  effective  only  while  there  is 
water  within  them,  while  the  "seal,"  as  the  water  within  the 
trap  is  called,  is  intact;  but  there  are  a  number  of  causes 
which  unseal  the  trap. 

Among  the  causes  of  unsealing  traps  are  evaporation  of  the 
water  through  disuse,  forcible  ejection  of  seal  through 
momentum  and  force  of  flush,  or  loss  of  seal  through  some 
waste  paper,  etc.,  being  left  in  trap  and  emptying  the  water 
by  capillary  attraction. 

The  water  in  the  trap  of  a  fixture  may  also  be  lost  some- 


48  HOUSING  HYGIENE 

times  by  "siphonage,"  or  by  the  action  of  a  large  column 
of  water  descending  with  great  momentum  down  the  vertical 
pipe  with  which  the  trapped  fixture  is  connected,  such  force 
being  sufficient  to  siphon  out  the  seal,  or  contents  of 
trap. 

Fouling  of  the  Seal. — The  "seal,"  or  contents  of  the  trap, 
may  also  be  fouled  by  constant  and  long  contact  with  the 
foul  air  in  the  pipes,  which  foul  air,  owing  to  heat  and  decom- 
position within  the  pipes,  is  under  increased  pressure. 

Protection  against  Loss  of  Seal. — Evaporation  may  be  pre- 
vented by  frequent  use  of  the  fixture,  or  by  filling  up  the  trap, 
when  disused,  by  some  non-evaporable  fluid,  like  oil,  etc., 
while  the  loss  of  seal  by  momentum  and  capillary  attraction 
must  be  prevented  by  care  in  use  of  fixture  and  flushing 
apparatus. 

To  prevent  the  fouling  of  the  seal  by  "back  pressure," 
and  its  withdrawal  by  "  siphonage,"  special  "  air  pipes,"  or 
so-called  "  vent,"  or  "  back-air-pipes,"  are  provided,  which 
run  through  the  house  vertically,  the  same  as  the  other  pipes, 
and  which  are  connected  by  branches  to  the  crown  of  every 
trap  of  every  fixture,  and  serve  the  sole  purpose  of  preventing 
siphonage  and  back  pressure. 

The  prevention  of  siphonage  is  accomplished  by  furnishing 
to  each  trap  a  column  of  air  which  may  be  drawn  upon  in 
lieu  of  the  seal,  while  fouling  of  the  water  in  the  trap  by 
back  pressure  is  prevented  by  providing  an  escape  of  the  air 
under  pressure  up  into  the  vent  pipes. 

The  vent  pipes  are  made  of  cast  iron.  • 

Instead  of  providing  vent  pipes,  there  are  sometimes 
provided  so-called  "non-siphoning- traps,"  made  and  shaped 
so  as  to  contain  a  large  volume  of  water  which  may  be  diffi- 
cult or  impossible  to  empty  by  siphonage. 

The  sizes  of  plumbing  pipes  vary  from  1|  inches  in  diameter 
of  small  branch  waste  pipes,  to  waste  pipes,  3  inches;  vent 
pipes,  2  to  3  inches;  soil  pipes,  4  to  5  inches;  and  house  drains, 
5  to  6  inches. 

The  whole  plumbing  system  is  ventilated  by  vertical  pipes 
led  through  the  roof  and  left  open  to  the  outside  air,  while 


HOUSE  CLEANING  49 

air  from  the  outside  is  provided  by  means  of  the  "fresh-air 
inlet,"  which,  beginning  with  an  air  box  in  the  sidewalk, 
runs  into  the  house  drain,  inside  of  the  main  trap,  by  a  4- 
inch  iron  pipe.  The  vent  pipes  also  aid  the  ventilation  within 
the  pipes. 

The  water  closet  is  the  most  important  fixture  within  the 
house.  It  should  be  made  of  porcelain  in  one  piece,  trap  and 
fixture,  with  smooth  surface  and  easily  cleaned.  The  wash 
down,  siphon,  and  "dececo"  forms  are  the  best. 

Water  closets  are  not  flushed  directly  from  the  wat^er  service 
pipe  for  fear  of  contaminating  the  water  supply,  but  are 
flushed  indirectly  through  cisterns  placed  at  least  4  feet  above 
them,  which  cisterns  are  automatically  filled  and  emptied  by 
the  pulling  of  a  chain  lifting  a  plug  out  of  the  socket  and 
flushing  through  flush  pipe  into  closet.  There  are  several 
improvements  upon  this  common  method  of  flushing,  one 
of  them  being  the  "Kenney  flushometer,"  dispensing  with 
the  separate  tank,  at  the  same  time  preventing  a  direct 
connection  with  the  water-supply  pipes. 


HOUSE  GLEANING. 

Dangers  of  House  Impurities  to  Health. — ^The  impurities 
which  are  found  in  houses  are  due  to  various  sources,  and 
may  be  divided  in  the  following  classes:  household  waste 
matter,  waste  water  and  sewage,  gases  and  poisons,  dirt  and 
dust,  organic  matter,  moulds  and  fungi,  bacteria  and  micro- 
organisms, domestic  animals,  insects  and  parasites. 

Household  waste  matters  in  the  form  of  rags,  cloths,  rubbish, 
papers,  etc.,  may  become  a  nuisance  in  the  house  on  account 
of  the  foul  odors,  of  the  organic  decomposition  upon  them,  by 
containing  insects,  parasites,  and  germs,  and  serving  as 
vehicles  for  transmission  of  disease  germs. 

Waste  waters,  garbage,  and  sewage  contain  easily  decom- 
posed organic  matter,  breed  insects  and  fouls  odors,  and  are 
dangerous  as  vehicles  of  disease  germs. 

The  gases  which  may  occasionally  be  found  in  the  house 
4 


50  HOUSING  HYGIENE 

are  an  excess  of  carbon  dioxide  and  carbon  monoxide  from 
leakage  of  illuminating  gas,  smoke  from  chimneys,  sulphur 
gases  from  decomposing  products,  sewer  air,  etc.  Their 
danger  to  health  need  not  be  gone  into  here. 

The  actual  toxic  elements  which  may  be  found  within 
the  house  are  the  poisons  in  the  dirt,  dust,  air,  and  water, 
such  as  arsenic  from  the  wall  papers,  lead  from  water  pipes, 
etc. 

The  dirt  found  in  a  house  consists  of  various  substances 
and  detrita  of  substances,  inorganic  and  organic,  which  are 
either  brought  into  the  house  from  the  outside  upon  the 
clothes,  shoes,  and  bodies  of  persons,  or  which  are  blown 
into  the  house  by  wind  through  doors  and  windows;  or  the 
dirt  may  be  due  to  processes  carried  on  within  the  house. 

House  dirt  and  dust  may  consist  of  particles  of  soil,  earth, 
brick,  wood,  plaster,  hair,  street  dust,  manure,  ashes,  excreta, 
dried  sputum,  pollen  of  flowers,  pulverized  fabrics,  fungi, 
moulds,  etc. 

Dust  is  dried  and  pulverized  dirt  floating  in  the  air,  and 
its  source  is  the  same  as  that  of  dirt. 

Dirt  and  dust  may  also  contain  particles  from  scales  of 
the  skin  of  persons  suffering  from  smallpox,  scarlet  fever, 
measles,  also  of  parasitic  diseases.  Dust  may  also  contain 
some  pathogenic  microorganisms,  as  diphtheria,  tubercle 
bacilli,  etc. 

The  dangers  of  dirt  and  dust  to  health  are  self-evident. 
They  may  be  mechanically  irritant  to  eyes  and  the  mucous 
membranes  of  nose  and  throat,  and  through  the  pathogenic 
germs  may  be  causative  of  certain  infectious  diseases. 

Organic  matter,  moulds,  and  fungi  are  abundant  in  houses, 
especially  where  there  is  considerable  dampness;  some  of  the 
fungi,  such  as  those  of  "  haus-schwamm,"  and  "  dry  rot," 
may  be  irritants  to  the  respiratory  tracts. 

The  bacteria  and  microorganisms  in  general  which  may 
be  found  in  houses  are  very  numerous  and  of  varying  impor- 
tance, according  to  their  virulence.  They  may  cling  to  the 
dust  floating  in  the  room  air,  or  they  may  cling  to  the  various 
dirt,  insects,  animals,  and  matter  in  the  house 


HOUSE  CLEANING  51 

Domestic  Animals  and  Health. — Dogs,  cats,  birds,  etc., 
may  become  a  source  of  danger  to  health  by  their  excreta, 
by  the  diseases  from  which  they  may  suffer,  by  the  parasites 
which  they  may  carry,  and  by  the  pathogenic  germs  which 
they  may  transmit. 

House  Vermin  and  Health. — Though  not  exactly  domestic 
animals,  rats  are  almost  always  uninvited  inhabitants  of  most 
houses,  and  may  play  an  important  role  in  the  transmission  of 
certain  diseases,  like  plague,  with  which  their  connection  had 
been  clearly  proved,  ~and  which  they  may  transmit  either 
directly  by  their  bites,  or  indirectly  through  fleas,  lice,  and 
other  parasites  upon  them. 

Houses  may  be  teeming  with  various  parasites  and  insects, 
such  as  roaches,  beetles,  centipedes,  spiders,  waterbugs,  flies, 
fleas,  lice,  bed-bugs,  and  mosquitoes. 

The  very  presence  of  some  of  the  insects  named  is  a 
nuisance  because  of  their  appearance,  odor,  or  bites.  Some 
of  these  insects  feed  either  upon  their  human  hosts,  or  upon 
domestic  animals,  or  upon  the  food  of  their  hosts.  The  bites 
of  some  of  the  insects  may  become  fatal  when  they  are 
infected  with  some  disease  germs  like  plague,  etc.  They 
may  also  be  carriers  of  infective  germs  upon  their  bodies, 
legs,  and  wings,  and  may  cause  infection  directly  or  indi- 
rectly. 

Flies  as  propagators  of  typhoid  fever  in  their  travel  between 
privy  vaults,  manure  heaps  and  the  water,  milk,  and  food 
upon  which  they  swarm  are  well-known  offenders,  and  there 
is  reason  for  the  opinion  expressed  by  some  that  they  may 
also  spread  tubercle  bacilli  from  patients  and  their  sputa  to 
articles  of  food. 

The  role  of  the  mosquito  as  an  intermediate  host  of  the  germ 
of  malaria  and  yellow  fever  is  spoken  of  in  another  place,  and 
the  presence  of  these  insects  within  houses  may  become  a 
menace  to  the  life  and  health  of  house  dwellers. 

Prophylaxis. — The  warfare  waged  by  house  dwellers  against 
all  the  forms  of  dirt  enumerated  must  be  constant,  inter- 
minable, thorough,  and  remorseless. 

The  methods  of  prophylaxis  consist  in  the  prevention  of 


52  HOUSING  HYGIENE 

ingress  and  accumulation,  removal  by  cleaning,  and  destruc- 
tion by  cremation  and  disinfection. 

Waste  matter,  rubbish,  garbage,  etc.,  may  be  prevented 
by  prompt  cremation  of  all  such  matter,  by  collection  in 
tight  receptacles,  and  by  frequent  periodical  municipal  removal. 

Waste  water  and  sewage  are  made  harmless  by  disposing 
through  plumbing  fixtures  and  pipes. 

Proper  care  of  the  illuminating  and  heating  plants  and 
ample  ventilation  will  prevent  the  dangers  of  gases. 

The  non-use  of  arsenical  papers  and  lead  paints,  or  lead 
pipes,  will  prevent  these  poisons  in  the  air  and  water. 

Dirt  and  dust  in  houses  may  be  prevented  by  proper  tight 
construction  of  windows  and  doors  and  provision  of  some 
other  protected  openings  for  ventilation,  by  thorough  cleans- 
ing of  shoes  and  cloth  before  entering  the  house,  by  elimina- 
tion of  any  projections,  mouldings,  nooks,  and  corners  within 
the  rooms,  and  by  provision  for  the  dryness  and  perfect 
lighting  of  all  parts  of  the  house. 

Fungi  and  moulds  may  be  prevented  by  preventing  damp- 
ness and  darkness  in  any  part  of  the  house. 

Domestic  animals  should  not  be  kept  within  the  house, 
or,  if  kept,  should  be  daily  attended  to,  examined  for  symp- 
toms of  disease,  frequently  washed,  cleaned,  and  disinfected, 
and  prevented  from  depositing  their  own  excreta  within  the 
house,  or  bringing  in  any  from  outside  of  the  house. 

The  presence  of  insects  within  the  house  may  be  partly 
prevented  by  thorough  cleanliness,  by  absence  of  darkness 
and  dampness,  by  screening  windows,  doors,  and  other 
openings,  by  covering  with  wire  nets  any  and  all  edible 
materials,  by  spreading  borax  or  boracic  acid  mixed  with 
sugar,  or  by  destroying  them  by  arsenic,  formaldehyde,  or 
sulphur  disinfection  and  fumigation. 

Destruction  of  rats  is  a  difficult  matter,  and  may  perhaps  be 
accomplished  by  proper  vermin-proof  construction  of  houses, 
houses  without  hollow  spaces  and  places  for  their  habitat. 
Fumigation,  poisoning,  and  such  means  may  prove  valuable. 

The  prevention  of  the  incoming  of  the  fly  and  mosquito 
consists,  besides  the  above  numerated  measures,  also  in  the 


HOUSE  CLEANING  53 

thorough  sanitation  of  the  surrounding  grounds  and  area  of 
houses,  and  destruction  of  breeding  places  of  those  insects. 

Means  and  Methods  of  Cleaning. — ^The  common  methods  of 
house  cleaning  are  wrong  in  principle  and  faulty  in  practice. 
The  dry  method  of  cleaning  by  means  of  raising  the  dirt  and 
dust  by  feather  duster  and  dusting  rags  is  worse  than  letting 
the  dirt  and  dust  lie  undisturbed.  Nor  is  the  common  method 
of  cleaning  floors,  etc.,  by  spilling  water  upon  them  an  improve- 
ment upon  the  dry  method. 

The  ideal  method  of  cleaning  is  the  modern  suction  or 
vacuum  process  by  means  of  special  apparata  operated  by 
motors  driven  by  steam  or  electricty.  Some  of  these  vacuum 
cleaners  are  made  so  as  to  be  operated  by  hand,  but  are  not 
so  satisfactory. 

Damp-cloth  Method. — Apart  from  the  vacuum  cleaners,  the 
best  method  of  removing  dust  from  walls,  furniture,  etc.,  is 
by  means  of  damp  rags  applied  to  all  surfaces,  said  rags  then 
being  washed  and  boiled  in  water. 

Some  surfaces,  such  as  walls,  furniture,  metal  beds,  etc., 
may  advantageously  be  wiped  off  with  such  cloths  or  rags 
dampened  in  solutions  of  from  3  to  5  per  cent,  of  carbolic  acid, 
corrosive  sublimate  1  to  5000,  or  formalin  5  per  cent. 

Curtains,  carpets,  rugs,  and  similar  soft  stuffs  should  be 
removed  from  the  house  before  cleaning,  and  be  subjected 
to  boiling  or  steaming. 

Wooden  floors,  furniture,  wainscoting,  etc.,  in  houses  may 
be  cleansed  by  a  cloth  dampened  with  kerosene  oil,  and  then 
polished  with  other  oil  impregnated  cloths. 

Stone,  tile,  and  mosaic  floors  may  be  scrubbed  with  hot 
soap-suds  and  wiped  off  with  cloths  impregnated  with  carbolic 
acid. 

Evaporation  of  formalin  or  formaldehyde  may  advanta- 
geously be  used  in  clothes  closets,  attics,  etc.,  while  fumiga- 
tion with  sulphur,  if  properly  done,  will  destroy  all  insects 
and  parasites. 

Disinfection  by  chemical  or  gaseous  means,  as  described  in 
the  chapter  on  "Disinfection,"  should  be  practised  in  houses 
at  stated  and  frequent  intervals. 


54  HOUSING  HYGIENE 


THE  HOUSING  PROBLEM. 

The  "housing  problem,"  the  "housing  question,"  the 
"housing  of  the  workingman,"  or  "the  tenement-house 
problem"  are  terms  variously  applied  to  the  same  sanitary- 
social-economic  housing  problem,  which  is  one  of  the  burning 
questions  of  the  age. 

In  its  final  analysis  the  housing  problem  essentially  consists 
in  the  difference  between  housing  conditions  as  they  are  and 
housing  conditions  as  they  should  be  according  to  the  precepts 
of  housing  hygiene. 

The  housing  question  has  become  a  problem  only  since 
housing  hygiene  has  been  scientifically  established,  when 
sanitarians  have  studied  the  effects  of  defective  housing  condi- 
tions upon  individual  and  public  health,  when  rules  have 
been  laid  down  for  the  proper  sanitary  construction  and 
arrangements  of  human  habitations  so  as  to  influence  health 
beneficially  instead  of  injuriously  as  heretofore. 

Briefly  stated,  the  housing  problem  consists  in  the  following 
defective  housing  conditions,  and  the  task  of  removing  such 
conditions  and  providing  the  majority  of  the  population  with 
sanitary  dwellings. 

The  defective  conditions  in  housing  are  as  follows :  Too  great 
density  of  population  upon  given  areas;  overcrowding  in 
cities,  streets,  blocks,  houses,  and  rooms;  damp,  water-logged, 
filled-in  sites;  defective,  flimsy,  speculative,  and  cheap  con- 
struction; absence  of  damp-proof  insolation  and  water-proof- 
ing; non-fire-proof  construction;  absence  of  fire-protective 
appliances;  defective  construction  of  walls,  floors,  roofs,  etc.; 
improper  arrangement  of  rooms;  insufficient  window  space, 
absence  of  windows  and  openings  for  light;  defective  plants, 
fixtures,  and  pipes  for  artificial  illumination;  deficient  provi- 
sion for  adequate  ventilation;  faulty  methods  and  plants  for 
heating;  defective  installation  of  plumbing  fixtures  and  pipes; 
absence  of  provision  for  cleaning;  presence  of  dirt,  dust, 
insects,  and  germs.  The  above  are  some  of  the  conditions 
commonly  found  in  houses  of  the  poor. 


HOUSE  INSPECTION  55 

The  concentration  of  such  houses  in  certain  well-defined 
sections  of  cities;  the  congestion  of  populations  in  tenement 
houses  in  special  insanitary  overcrowded  districts;  the  in- 
creased adult  death  rate,  large  percentage  of  mortality  from 
infectious  disases,  and  an  appalling  infantile  rate  of  mortality 
are  some  of  the  concomitant  conditions  of  the  housing  problem. 

The  analysis  of  the  causes  of  faulty  housing-conditions  is 
within  the  province  of  the  social-economist  rather  than  that 
of  the  sanitarian,  the  purpose  of  the  latter  being  but  that  of 
showing  up  the  sanitary  defects  as  they  are  found,  noting  their 
effects  upon  individual  and  public  health,  and  devising  means 
for  improved  sanitary  construction  and  conditions  in  housing. 

The  remedies  for  faulty  housing  conditions  proposed  by  the 
social-economists  are  many  and  various;  the  remedies  pro- 
posed by  the  sanitarians  are  briefly  enumerated  as  follows: 
Sanitary  supervision  of  housing  conditions ;  sanitary  inspection  i 
of  existing  houses;  compulsion  of  owners  to  remedy  defects  ^ 
and  keep  houses  in  sanitary  condition;  legislation  restricting 
improper  use  of  building  areas  and  demanding  the  construc- 
tion of  houses  in  the  future  according  to  fast-laid-down  laws 
based  upon  housing  hygiene;  the  destruction  of  insanitary 
areas,  demolition  of  insanitary  houses,  and  a  complete  super- 
vision by  proper  expert  qualified  authorities  of  all  housing 
construction  in  the  future,  as  well  as  existing  houses  at  present. 


HOUSE  INSPECTION. 

Elements  of  Home  Inspection. — Sanitary  inspection  of 
houses,  whether  private  dwellings,  tenement  houses,  or 
any  other  buildings,  consists  in  a  thorough  examination  of 
the  whole  house,  with  the  purpose  of  discovering  (1)  defects 
in  construction,  (2)  defects  in  the  condition  of  various 
parts  of  the  house,  (3)  violations  of  laws,  rules,  and  regu- 
lations imposed  upon  buildings  of  the  character  by  various 
state  or  municipal  authorities. 

In  order  to  be  able  to  recognize  defects  and  note  viola- 
tions of  sanitary  laws,  the  inspector  must  be  thoroughly 
versed  in  the  various  sanitary  laws  of  his  part  of  the  country, 


56  HOUSING  HYGIENE 

and  must  have  a  thorough  and  complete   knowledge   of 
building  construction  and  house  sanitation. 

Details  of  House  Inspection. — For  a  better  review  of  house 
inspection  methods  the  object  of  inspection  must  be  sub- 
divided into  several  broad  groups.  Thus  the  objects  of 
house  inspection  may  be  classified  under  the  following 
subdivisions : 

1.  House  surroundings. 

2.  House  construction, 

3.  House  dampness. 

4.  Fireproof  precautions. 

5.  Lighting, 

6.  Heating. 

7.  Ventilation. 

8.  Water  supply. 

9.  Plumbing. 

10.  Care  and  cleanliness. 
^  House  Surroundings. — These  are  naturally  the  first  objects 
of  inspection.  The  surroundings  of  the  house;  the  proximity 
of  trees,  rivers,  lakes,  ponds,  etc.;  the  aspect  of  the  house 
with  relation  to  sun  and  wind;  the  configuration  of  the 
ground ;  the  elevation  above  sea  level ;  the  relation  of  eleva- 
tion to  adjoining  houses  and  plots;  the  presence  of  inclines, 
valleys,  and  hills  in  the  immediate  proximity;  the  nature, 
height,  and  condition  of  surrounding  houses;  the  nature, 
character,  and  materials  of  the  walks,  streets,  and  other 
spaces  in  the  surrounding;  the  nature  of  the  soil,  its  pre- 
meability,  character,  ground-water  level,  subjection  to  tides 
and  inundations,  etc.  All  the  above  points  are  proper  and 
necessary  subjects  of  careful  investigation,  inspection,  and 
examination  by  the  house  inspector  desiring  to  make  a 
com^jlete  inspection  and  survey  of  a  house. 

Having  inspected  and  noted  the  points  of  house  surround- 
ings, the  inspector  next  has  to  examine  the  site  of  the  building. 
The  character  of  the  site,  its  permeability,  bearing  capacity, 
dryness,  freedom  from  contamination,  and  many  other 
points  must  be  examined  for  the  effective  understanding 
of  many  features  of  the  house  depending  upon  the  site. 


HOUSE  INSPECTION  57 

House  Construction. — The  inspection  of  houses  during 
their  construction  is  the  duty  of  the  bureaus  of  buildings, 
etc.,  which  have  their  inspectors  of  masonry  construction, 
inspectors  of  ironwork,  inspectors  of  carpentry  and  joinery, 
etc.,  as  it  is  difficult  for  one  man  to  be  expert  in  all  branches 
of  building.  Such  inspectors  have  charge  of  the  corrections 
of  architect's  plans,  the  inspection  and  tests  of  the  quality 
and  strength  of  various  building  materials,  and  the  character 
of  workmanship  in  each  of  the  various  building  branches. 

The  house  inspector  more  often  has  to  do  with  buildings 
already  constructed,  and  his  duty  is  to  examine  the  condition 
of  the  various  parts  of  the  house  construction,  the  condi- 
tion of  the  frame  or  masonry  walls,  the  strength  of  the  beams, 
the  condition  of  the  walls,  sidewalks,  stairs,  partitions,  roof, 
eaves,  leaders,  doors,  windows,  and  all  the  other  numerous 
parts  of  the  constructed  house,  to  see  whether  they  are 
all  in  proper  condition,  have  not  deteriorated  since  the 
construction  so  as  to  become  a  nuisance,  and  be  detrimental 
to  health  and  dangerous  to  life. 

House  Dampness. — The  inspection  of  the  damp-proof 
quality  of  a  house  is  an  important  subject  of  house  sanitation. 

Knowing  the  causes  of  house  dampness,  the  inspector 
will  look  for  evidence  of  dampness  in  the  house,  in  the  walls, 
and  in  the  cellar.  As  a  rule,  it  is  not  difficult  to  judge  damp 
walls  from  dry  ones,  and  the  experience  of  the  dwellers  may 
at  times  be  relied  on  so  far  as  internal  dampness  is  concerned. 

The  search  of  the  causes  of  dampness  must  be  directed 
to  those  causes  which  act  upon  the  cellar  and  those  which 
act  on  the  walls.  Defects  in  construction,  newly  built 
houses,  absence  of  provisions  for  damp-proofing  the  walls, 
the  condition  of  the  roof,  gutters,  leaders,  etc.,  are  points 
to  be  carefully  noted. 

Dampness  due  to  conditions  in  the  cellar  is  still  more  im- 
portant. When  due  to  absence  of  provisions  for  isolation 
of  footings,  foundations,  and  walls  from  ground  to  entrance 
of  underground  water  it  is  the  most  difficult  to  remedy 
the  defects.  The  searching  for  the  hidden  causes  of  water 
in  cellars  presupposes  a  knowledge  of  the  various  sources 
as  indicated  in  the  chapter  on  Housing  Hygiene. 


58  HOUSING  HYGIENE 

Fireproofing. — ^The  measures  guarding  the  house  against 
fire  consist  in  the  proper  construction  as  well  as  in  the  pro- 
vision for  fire  escape. 

The  points  to  be  noted  are  the  material  of  walls,  floor, 
and  ceiling,  the  character  of  floor  joists,  partitions,  plastering, 
lathing,  the  presence  of  shafts,  courts,  and  wells  serving  as 
chimneys  for  air  currents,  to  protection  of  interior  wood- 
work, especially  near  chimneys  and  fireplaces,  the  char- 
acter of  the  roofing,  openings  from  dumb-waiter  shafts, 
etc.,  the  construction  and  materials  of  stairways,  the  presence 
of  enclosed  spaces  under  stairways,  etc.  The  construction, 
and  condition  of  fire  escapes  is  an  important  item  of  inspec- 
tion in  this  respect.  Whether  constructed  of  iron  or  not,  the 
kind  and  strength  and  thickness  of  the  iron,  the  manner  of 
fastening  of  the  balconies  to  the  walls  by  nuts  and  rivets, 
the  balconies,  rails,  guards,  standards,  battens,  size  and 
character  of  balcony  openings,  the  presence  of  gooseneck 
and  drop-ladders,  the  construction  of  ladders,  the  angle 
of  inclination,  the  size,  thickness,  and  strength  of  the  treads, 
the  number  of  fire  escapes,  and  a  great  many  other  minor 
points  must  be  noted  for  a  careful  inspection  of  fire  escapes. 

Lighting. — The  inspection  of  the  natural  and  artificial 
modes  of  lighting  consist  in  the  following  points:  number 
of  rooms,  number  of  windows  in  each,  size  of  windows, 
location  and  character,  with  regard  to  floor  and  ceilings; 
number  of  panes,  character  of  glass,  size  and  height  of 
rooms,  color  of  walls  and  ceilings,  presence  and  size  of 
light  shafts  and  open  courts,  skylights  and  windows  in  halls 
and  over  stair  wells,  of  rooms  without  openings  into  street 
or  yard,  width  of  street,  yard,  courts,  etc. 

The  inspection  of  artificial  source  of  illumination  con- 
centrates upon  the  following  points:  Whether  central  or 
local,  gas,  electricity,  or  oil,  character  of  wire  or  pipe  installa- 
tion, quality  and  workmanship  of  installed  service,  tightness 
of  pipes,  presence  of  meters,  quality  of  fixtures,  character 
of  tips,  burners,  and  protection  of  nearby  surfaces  from 
fire,  etc.,  number  of  fixtures,  their  height  from  floor,  prox- 
imity to  doors,  walls,  etc. 


HOUSE  INSPECTION  59 

Heating. — ^When  heating  methods  are  but  local,  i.  e., 
when  house  is  heated  by  grates  or  stoves,  the  inspection  is 
comparatively  of  but  little  difficulty.  More  difficult  is  the 
inspection  of  a  central  heating  plant. 

The  points  of  inspection  are  at  first  the  adecjuacy  of 
the  heating  system,  its  ability  to  raise  the  temperature  of 
all  the  rooms  to  at  least  70°  F. 

Various  factors  enter  into  the  calculation  of  the  necessary 
heating  capacity  of  central  plants  and  the  pipes  and  radiators 
serving  them.  The  cubic  capacity  of  the  rooms,  the  height 
and  floor  space,  the  character  of  the  building  (its  material 
and  construction),  the  exposure  to  wind  and  sun,  the  prox- 
imity of  trees,  etc.,  all  the  above  enter  as  factors  in  the 
problem  of  adequately  heating  a  house. 

The  inspection  of  the  plant  itself  divides  itself  into  the 
inspection  of  the  furnace,  of  boiler,  of  pipes  in  the  cellar, 
the  inspection  of  the  piping  system  and  of  the  radiators. 

The  position  of  the  furnace,  the  character  of  the  cold- 
air  box,  the  place  where  the  cold-air  box  ends,  the  form 
of  grate,  the  presence  of  evaporators,  and  of  the  control 
to  prevent  overheating  the  furnace  are  important  points 
of  inspection  of  hot-air  furnaces.  There  are  a  number 
of  important  items  of  inspection  of  hot  water  and  steam 
boilers,  their  capacity,  the  water  and  steam  gauges,  the 
pressure  and  safety  valves,  the  firing  box,  the  grate,  the 
connections,  the  protections  of  pipes  in  cellar  by  asbestos 
packing,  the  direction  of  pipes,  the  size  of  ascending  risers 
and  descending  pipes,  the  form  of  expansion  tank  in  hot 
water  heating,  the  system  and  kind  of  steam-heating  pipes 
used,  the  number  of  section  of  radiators,  their  proximity 
to  windows,  etc. 

Ventilation. — The  following  are  some  of  the  points  of 
inspection  in  the  means  and  methods  of  ventilating  houses. 

The  material  and  form  of  house  construction;  the  floor 
space  of  rooms,  their  cubic  capacity,  the  number  and 
character  of  windows  and  other  openings;  the  number  of 
persons  residing  in  each  room;  the  character,  size,  bulk, 
and  kind  of  furniture  in  the  house;  the  system  of  heating 


60  HOUSING  HYGIENE 

and  illumination,  the  presence  of  permanent  openings  into 
the  external  air,  the  temporary  openings,  the  presence  of 
chimney  openings,  grate  fires  and  stoves,  and  the  presence 
of  mechanical  means  of  ventilation. 

The  inspection  of  the  mechanical  ventilating  plant  consists 
in  a  thorough  examination  of  the  motor  power  and  motors, 
the  various  fans,  etc.,  the  tightness  of  central  and  local 
ducts,  inlets  and  outlets,  the  placing,  size  of  inlets  and 
outlets,  the  measure  and  control  of  the  humidity  of  the  air, 
velocity  of  air  going  through  inlets,  etc. 

An  examination,  chemical  and  bacteriological,  of  the  air 
in  the  room  may  be  necessary  to  determine  the  impurities 
in  the  air,  and  their  improvement.  This  will  be  described 
later. 

Water  Supply.  —  In  cities  with  a  central  water-supply 
system  the  inspection  of  the  water  supply  of  a  house  con- 
sists simply  in  the  examination  of  the  material,  size,  and 
kind  of  main  service  pipe,  presence  of  stopcocks  and  water 
meters,  and  an  examination  of  the  number,  kind,  material 
location,  and  size  of  house  service  pipes  and  faucets. 

In  rural  places,  where  a  local  supply  is  the  source,  the 
inspection  of  the  sources  and  character  of  the  water  supply 
is  a  very  difficult  matter  at  times.  Such  an  inspection 
embraces  the  study  of  all  the  sources  of  water  gupply,  the 
tracing  of  their  sources,  the  examination  of  the  ground, 
the  precautions  against  contamination  with  sewage,  the 
proximity  to  stables,  vaults,  and  cesspools,  the  material 
and  kind  of  receptacles,  pipes,  etc.  It  may  be  necessary 
to  make  a  chemical  and  bacteriological  examination  of 
the  water. 

Plumbing. — The  inspection  of  plumbing  consists  in  the 
examination  of  the  material,  kind,  and  condition  as  well 
as  workmanship  of  the  fixtures  and  the  piping  which  con- 
ducts the  waste  water  into  the  street.  The  number,  kind, 
and  material  of  the  sinks,  laundry  tubs,  washbasins,  bath- 
tubs, and  water  closets,  their  condition  and  connection 
with  the  pipes;  the  forms,  material,  and  kind  of  trap  of  those, 
as  well  as  distance  of  the  trap  from  the  fixtures;  the  kind 


HOUSE  INSPECTION  61 

of  connection  of  the  traps  and  branch  waste  and  soil  pipes 
with  the  main  soil  and  waste  pipes;  the  manner  and  form 
of  venting,  or  "back  airing"  of  the  traps;  the  material, 
size,  form,  and  condition  of  the  vertical  soil,  waste,  vent,  and 
leader  pipes;  the  manner  of  their  connection  with  the  house 
drain;  the  material,  size,  kind,  inclination,  fall,  and  con- 
dition of  the  house  drain;  its  connection  joints,  bends,  and 
the  number  of  openings  on  the  house  drain  and  the  manner 
of  their  closing  by  covers  or  screw  ferrules;  the  presence  of 
main  house  trap,  fresh-air  inlet,  and  their  condition;  the 
material  and  condition  and  size  of  the  outside  leaders, 
gutters,  and  eaves.  All  the  above  are  items  to  be  carefully 
examined  for  defects. 

Wherever  plumbing  pipes  are  exposed  their  inspection 
is  ocular  and  presents  little  difficulty,  although  at  times 
sand  holes,  small  crevices,  and  puttied-up  openings  may 
be  overlooked.  Wherever  the  pipes  are  hidden  the  examina- 
tion of  the  plumbing  System  must  be  supplemented  by 
either  the  "peppermint"  test  or  the  "smoke"  test. 

The  peppermint  test  is  based  upon  the  fact  that  any 
pungent  volatile  substance  will  escape  from  defects  in  pipes 
provided  all  other  openings  are  closed.  The  method  of 
applying  the  peppermint  test  is  as  follows:  Several  ounces 
of  peppermint  oil  (some  other  pungent  substance  may 
be  used)  are  poured  into  some  opening  in  the  pipe  system, 
preferably  into  the  opening  of  one  of  the  pipes  on  the  roof. 
The  opening  of  the  pipe  into  which  the  oil  had  been  put, 
as  well  as  all  other  openings  on  the  roof,  are  then  closed 
with  waste  paper  or  plugs,  and  the  oil  allowed  to  be  distributed 
through  the  pipes.  The  main  house  drain  being  closed 
to  the  escape  of  the  smell  by  the  main  house  trap,  the  odor 
is  held  within  the  pipes  and  will  escape  from  any  slight 
crevice,  hole,  or  opening.  The  pungency  of  the  oil  is  in- 
tensified by  the  addition  at  the  same  time  of  hot  water. 
None  of  the  fixtures  are  to  be  used  during  test,  in  order 
that  the  peppermint  may  not  escape  from  them. 

The  smoke  test  is  said  to  be  a  more  thorough  test  for 
the  pipes.     It  is  applied  by  smoke  being  introduced  into 


62  HOUSING  HYGIENE 

the  pipe  system  after  the  opening  of  vertical  pipes  are  closed 
with  plugs.  Special  smoke-producing  bombs,  rackets,  and 
appliances  are  sold  by  dealers  for  the  test. 

Cleanliness. — The  cleanliness  and  condition  of  any  and 
all  parts  of  the  house  are  inspected  by  going  through  all 
parts  and  corners  of  the  house  and  seeking  for  refuse  and 
dirt. 

HOUSE  INSPECTION,  SPECIAL. 

House  Dai^ipness. 

Signs. — Musty,  mouldy  odor. 

Wall  spots  and  discoloration. 

Dry  rot  (destruction  of  timber  by  fungus). 

EflBorescence  of  masom-y. 

EflPects  on  objects:     Iron  rusts;  salt,  etc.,  deliquesces; 
shoes,  etc.,  mildew;  quicklimes  slake. 

Fungi,  mould  develop. 

Relative  humidity  of  room  increases. 
Test  for  Amount  of  Moisture  in  Walls, — Remo"\'e  with  trowel 
from  several  places  in  the  wall  10  grams  of  mortar  and  put 
same  in  hermetically  closed  bottle.  The  mortar  in  the 
bottle  is  then  weighed  (with  deduction  for  the  bottle)  and 
the  same  of  mortar  is  then  dried  by  a  blast  of  hot  air  (100° 
C.)  which  has  been  pre^'iously  freed  from  its  moisture  and 
CO2  by  lime  and  sulphuric  acid.  After  drying  for  one 
hour  the  samples  of  mortar  are  weighed,  the  difference 
in  weight  between  the  dried  .and  crude  state  being  the 
amount  of  moisture  in  sample  and  wall. 

Tracing  Soueces  of  Water  ix  Cellars. 

Examine  topography  of  site,  character  of  soil,  ground- 
water level,  and  material  of  foundation  and  footings. 
Quantity  of  water. 

Constancy  of  the  water,  temporary  or  permanent. 
Level  of  the  water. 
Point  of  entrance. 


EXAMINATION  OF  AIR  IN  ROOMS  63 

Depth  of  point  of  entrance. 

Mode  of  entrance. 

Physical  examination:  color,  clearness,  taste,  odor. 

Chemical  examination:  nitrites,  nitrates,  ammonia. 

Color  test  with  uranine,  fuchsine,  etc.  Put  coloring  matter 
into  fixture  suspected  and  watch  for  appearance  of  color  in 
the  cellar  water. 

Examination  of  Air  in  Rooms. 

The  qualitative  and  quantitative  determination  of  impuri- 
ties in  the  air  of  rooms  is  a  very  difficult  process,  as  there  is 
no  method  as  yet  discovered  to  find  out  the  character  and 
amount  of  the  various  organic  emanations  from  the  human 
body  which  make  the  air  in  inhabited  rooms  so  much  more 
poisonous  than  air  simply  supercharged  with  COg  or  other 
gases.  According  to  some  investigators  the  increased  tem- 
perature of  inhabited  rooms  plays  a  very  important  role  in 
the  air  deterioration.  However,  as  the  amount  of  COg  in  the 
air  of  inhabited  rooms  seems  to  increase  in  the  proportion  of 
the  vitiation  of  the  air  by  the  general  organic  emanations 
of  persons  present,  the  amount  of  COg  has  been  hitherto 
regarded  as  a  standard  for  the  amount  of  air  deterioration. 
There  are  a  number  of  ingenious  tests  for  the  determination 
of  the  amount  of  COg  in  the  air  most  of  them  being  quite 
complicated  and  requiring  a  complex  process  of  chemical 
analysis  and  calculations.  The  following  are  the  essential 
points  of  the  standard  tests: 

Pettenkoifer's  Test. — ^Barium  hydrate  mixed  with  carbonic 
acid  produces,  besides  water,  an  insoluble  salt — barium  car- 
bonate. If  we  then  mix  a  known  amount  of  barium  hydrate 
in  solution  with  a  known  amount  of  air,  part  of  the  barium 
hydrate  will  go  to  form  the  barium  carbonate  with  the  car- 
bonic acid  in  the  air  and  part  will  be  left  undissolved.  We 
can  then  calculate  the  difference  in  the  amount  of  the  barium 
hydrate  in  the  solution  before  its  mixture  with  the  air  and 
after,  which  difference  will  indicate  the  amount  of  carbonic 
acid  in  the  examined  air.     The  amount  of  barium  hydrate  is 


64  HOUSING  HYGIENE 

determined  by  a  standard  solution  of  oxalic  acid.  The  tests 
must  be  made  at  a  temperature  of  32°  F.  and  barometric 
pressure  from  thirty  inches  of  mercury,  or  corrections  must 
be  made  as  to  this  temperature  and  barometric  pressure. 
The  test  is  ver)'  complicated  and  requires  special  apparatus 
and  great  skill. 

Wolpert's  Test. — ^In  this  test  a  solution  of  carbonate  of 
soda  colored  red  by  phenolphthalein  is  used  to  mis  with  a 
given  volume  of  air  to  be  examined.  AMien  mixed  with  the 
examined  air  part  of  the  carbonate  of  soda  unites  with  the 
carbonic  acid  and  forms  bicarbonate  of  soda,  thus  lessening 
the  alkalinit}'  and  also  the  red  color  of  the  solution.  The 
more  carbonic  acid  in  the  examined  air  the  quicker  the  dis- 
appearance of  the  red  color.  Tlie  apparatus  is  furnished 
with  a  scale  so  that  the  approximate  amount  of  carbonic  acid 
is  determined. 

Angus  Smitli's  Test. — Lime  water  when  mixed  with  car- 
bonic acid  gets  cloudy  and  precipitates.  Six  bottles  of  a 
capacity-,  respectively,  of  150,  200,  2.50,  300,  350,  and  450  c.c. 
are  stoppered  with  rubber  caps,  and  into  each  bottle  15  c.c. 
of  fresh  lime  water  is  put.  The  bottles  are  then  filled  with 
the  air  of  the  room  and  the  smallest  bottle  which  shows  a 
precipitate  is  noted.  The  amount  of  CO2  which  is  present 
in  the  air  of  the  bottles  when  they  get  cloudy  is — in  the 
sized  bottles  enumerated  above — as  follows:  1.6,  1.2,  1, 
0.8,  0.7,  and  0.5  per  1000,  so  that  if  the  smallest  bottle  gets 
a  precipitate  on  mixing  of  the  lime  water  in  the  flask  with 
the  air  of  the  room  the  amount  of  COg  is  0.16  per  10,000.  or 
about  four  times  the  normal  amount. 

ReL-^TIVE   Hr-AIIDITT. 

The  relative  humidity  of  the  air  of  rooms  may  be  tested 
bv  means  of  various  instruments  called  hygrometers,  psy- 
chrometers,  etc. 

The  easiest  method  of  determining  relative  humidity  is  by 
means  of  the  wet  and  dry  thermometers,  in  an  instrument 
called  the  hygrodeik.  The  instrument  consists  of  two  ther- 
mometers attached  to  a  chart,  one  thermometer  being  dry, 


QUE  ST  I  ox  S  65 

while  the  other  is  kept  wet  by  means  of  a  cotton  wick  im- 
mersed in  a  glass  water-filled  vessel.  The  calculation  of  the 
relative  humidity  of  air  is  made  on  the  difference  in  the  tem- 
perature shown  by  the  dry  and  wet  thermometers,  and  the 
ready  chart  makes  it  easy  by  simple  manipulation  to  find  out 
in  a  moment  not  only  the  relative  humidity,  but  also  the 
amount  of  moisture  in  grains  per  cubic  foot  of  air. 

QUESTIONS. 

Give  definition  of  hoiising  hygiene. 

■^Tiat  are  the  relations  of  housing  to  health? 

What  are  the  influences  of  tu-ban  location  of  houses  ? 

What  are  the  influences  of  density  of  population? 

Give  examples  of  relation  of  density  of  population  to  infant  mortahty. 

State  the  influence  of  improved  housing  conditions. 

WTiat  materials  are  used  for  house  construction? 

"What  are  the  advantages  and  disadvantages  of  wood? 

What  are  the  advantages  and  disadvantages  of  stone,  brick,  iron? 

What  is  hme,  terra  cotta,  portland  cement,  concrete? 

"^Tiat  is  natural  cement,  reinforced  concrete? 

Emmierate  fire-resisting  building  materials. 

"RTiat  does  "fire-proof"  construction  mean? 

What  are  the  apphances  for  fire-escape,  for  fire  extinguishing? 

State  what  harm  to  health  there  is  in  damp  houses. 

T\Tiat  are  the  causes  of  house  dampness? 

TVTiat  are  the  causes  of  wet  cellars  ? 

What  are  the  best  means  for  preventing  dampness  m  houses? 

What  are  the  three  principal  methods  of  fire-proof  construction? 

■RTiat  are  the  relations  of  the  site,  soil,  and  aspect  to  health? 

Give  the  details  of  house  inspection? 

What  does  inspection  of  plumbing  consist  in? 

■^"hat  is  the  peppermint  test? 

What  are  the  signs  of  house  dampness? 

What  is  the  test  for  the  amount  of  moisture  in  walla? 

How  would  you  trace  the  sources  of  water  in  cellars? 

What  are  footings,  and  how  constructed? 

How  should  cellars  be  constructed? 

WTiat  are  the  methods  of  wall  construction? 

What  are  the  sanitary  demands  upon  floor  construction? 

State  the  proper  construction  of  roofs. 

W"hat  are  the  sanitarj-  requirements  of  proper  inner  construction? 

What  is  the  relation  of  sunlight  to  health? 

Upon  what  does  the  amount  of  natural  Ught  in  houses  depend? 

What  should  be  the  window  area? 

What  are  the  sanitarj-  requirements  of  artificial  illumination? 

What  is  acetylene  gas,  how  produced? 

What  is  the  difference  betv\-een  coal  and  water  gas? 

WTiat  are  the  sanitarj-  requirements  of  gas  illumination? 

Give  the  composition  of  atmospheric  air. 

What  are  the  variations  of  O  and  CO2? 

"tMiat  are  the  sources  of  house  impurities  in  air? 

What  is  the  relation  of  increase  in  COi  and  deterioration  of  air? 

WTiat  are  "absolute"  and  "" relative"  humidity? 

6 


66  HOUSING  HYGIENE 

How  is  air  in  rooms  examined? 

What  is  ventilation,  and  why  necessary? 

What  is  the  quantity  of  air  needed  for  person  per  hour  ? 

What  is  natural,  artificial,  and  mechanical  ventilation? 

What  are  the  principal  means  of  natural  ventilation? 

What  are  means  of  artificial  ventilation? 

What  are  the  relations  of  heating  to  ventilation  ? 

What  are  the  advantages  of  mechanical  ventilation? 

WTiat  are  the  effects  of  a  too  high  or  a  too  low  temperature? 

What  are  the  effects  of  a  too  sudden  change  in  temperatures? 

What  is  proper  temperatm-e  of  rooms? 

What  are  the  hygienic  demands  from  a  system  of  house  heating? 

What  are  the  three  methods  of  heating? 

What  are  the  objections  to  local  heating? 

What  are  the  advantages  of  central  heating? 

Name  the  principal  systems  of  central  heating. 

What  are  the  advantages  and  disadvantages  of  furnace  heating? 

What  are  the  advantages  and  disadvantages  of  hot- water  heating? 

What  are  the  advantages  and  disadvantages  of  steam  heating  ? 

What  are  impurities  commonly  found  in  water? 

What  do  we  mean  by  "hard"  and  "soft"  water? 

What  are  the  sources  of  domestic  water  supply? 

What  are  the  objections  to  each  of  them? 

What  are  the  common  means  of  domestic  water  purification? 

Name  the  methods  of  sewage  disposal. 

"V^Tiat  are  the  objections  to  the  dry  system  of  disposal  of  sewage? 

Describe  a  privy-vault  and  state  objections  to  it. 

What  is  a  cesspool  and  what  are  the  objections  to  it? 

Describe  a  system  of  field  irrigation 

WTierein  does  a  system  of  house  plumbing  consist? 

What  are  the  materials  of  house  plumbing  fixtures  and  pipes? 

What  is  sewer  air  and  how  prevented  in  houses? 

What  are  the  causes  of  loss  of  "seal"  in  traps? 

How  is  it  prevented? 

How  is  the  plumbing  system  ventilated? 

How  are  water  closets  flushed? 

Name  the  various  impurities  found  in  houses. 

What  are  the  dangers  of  dust,  dirt,  and  organic  matter? 

What  are  the  dangers  of  domestic  animals  and  insects  in  houses? 

What  are  the  methods  of  prophylaxis  against  those  dangers? 

What  are  the  common  methods  of  house  cleaning  ? 

What  are  proper  methods  of  house  cleaning? 

What  is  meant  by  the  "housing  problem"? 

What  are  the  remedies  commonly  advocated  for  its  solution? 


CHAPTER  III. 

SCHOOL  HYGIENE. 

RELATION  OP  SCHOOLS  AND  SCHOOL  LIFE  TO  HEALTH. 

Scope  of  School  Hygiene. — School  hygiene  is  that  branch  of 
pubHc  hygiene  deahng  with  the  effects  of  schools  and  school 
life  upon  health,  the  causes  of  such  effects,  and  the  means  to 
preserve  and  promote  the  health  of  the  school  children,  and 
hence  the  public  health. 

There  are  in  the  United  States  nearly  20,000,000  school 
children  between  the  ages  of  six  and  eighteen  who  are  subject 
to  the  influences  of  schools  and  school  life  during  a  large  part 
of  the  day  and  a  greater  apart  of  the  year,  and  during  a  period 
of  life  when,  by  reason  of  undeveloped  physical  and  mental 
faculties  they  are  peculiarly  influenced  by  any  and  all  environ- 
mental conditions  in  which  they  are  compelled  to  live. 

The  ill  eflEects  of  school  life  on  the  health  of  children  manifest 
themselves  in  the  following  ways : 

1.  Defective  development  of  the  child. 

2.  Retardation  of  growth. 

3.  Actual  physical  defects  developed  by  school  life. 

4.  Special  "school  diseases." 

5.  Defective  mental  development. 

There  are  ample  statistical  data  to  prove  the  defective 
physical  development  of  a  large  percentage  of  the  school  chil- 
dren, defects  in  a  great  part  due  to  school  influences. 

According  to  the  investigations  of  Danish,  Swedish,  and 
Norwegian  authorities  it  was  found  that  the  percentage  of 
physically  defective  children  were  as  follows: 

Boys.  Girls 

Per  cent.  Per  cent 
Kopenhagen  (Hertel)    .      .777777      .      31.1  39.4 

Danish  Commission 29.0         41.0 

Sweden  (Key) 34.4         61.7 

Norwegian  Commission 21.9         36.6 

(67) 


68  SCHOOL  HYGIENE 

According  to  an  investigation  undertaken  in  Washington, 
D.  C,  during  1908,  by  the  "Presidents'  Homes  Commission," 
it  was  found  that  out  of  43,005  pupils  (29,598  white  and 
13,407  colored)  there  were  15,304  defectives,  or  35.5  per 
cent. 

According  to  an  examination  undertaken  by  the  inspectors 
of  the  New  York  City  Department  of  Health,  out  of  100,000 
examined  children  there  was  66  per  cent,  physical  defectives. 

The  following  detailed  report  of  the  examination  by  this 
Department  of  78,401  children  is  of  extreme  interest: 

Per  cent. 

Number  examined. 78,401  100.0 

Total  number  needing  treatment       ....  56,259  71.7 

Bad  nutrition 4,921  6.3 

Anterior  cer\T.cal  glands 29,177  37.2 

Posterior  cer^dcal  glands 8,664  11.0 

Chorea 1,380  1.7 

Cardiac  disease 1,096  1.4 

Pulmonarv 757  0.9 

Skin  disease 1,558  1.9 

Defective  spine  .           424  0.5 

Defective  chest 261  0.3 

Defective  extremities 550  0.7 

Defective  ^^sion 17,928  22.8 

Defective  hearing 869  1.1 

Defective  nasal  breath 11,314  14.0 

Defective  teeth 39,597  55.0 

Defective  palate 831  1.0 

H-^-pertrophied  tonsils 18,306  23.3 

Postnasal  catarrh 9,438  12.0 

Defective  metaboHsm 1,853  2.3 

The  effects  of  school-life  on  growth  in  height  and  weight  are 
difficult  to  study,  as  there  are  very  few  children  who  are  out  of 
school  in  all  countries  where  school  attendance  is  compulsory, 
and  there  are  therefore  few  with  whom  a  comparison  may  be 
made.  A  study,  however,  has  been  made  of  the  difference  in 
the  growths  during  the  first  school  year,  and  also  during  the 
periods  of  the  year  free  from  school  attendance. 

According  to  Smith-]Monard  there  was  a  difference  in  the 
rate  of  increase  in  weight  and  height  of  children  during  the 
sever^th  year  of  life  according  to  whether  they  attended  school 
or  not,  as  follows: 

Inc.  M'eight.  kg.  Inc.  height,  cm. 

Boys.       Girls.  Boys.        Girls. 

Not  amending 2.2  1.9  7.4  5.6 

Attending  school 1.5  0.6  4.2  4.5 

Increase  of  non-school  over  school     .      0.7  1.3  3.2  1.1 


SCHOOL  DISEASES  69 

or  an  increase  of  30  to  60  per  cent,  in  weight  and  an  increase  of 
30  to  40  per  cent,  in  height  of  children  not  attending  school 
over  children  attending  school  in  their  seventh  year  of  life, 
showing  plainly  the  effect  of  school  life  upon  the  growth  of 
children. 

There  are  also  certain  periods  of  school  life  when  children 
not  only  stop  gaining  in  height  and  weight,  but  actually  lose 
weight;  this  is  notably  the  case  during  examination  periods. 
Thus,  it  was  found  by  Ignatieff  (]Moscau)  that  79  per  cent,  of 
pupils  lost  in  weight  during  examinations,  and  in  Stara  Zagora 
(Bulgaria)  it  has  been  found  that  68  per  cent,  of  the  children 
lost  in  weight  during  the  same  periods. 

School  Diseases. — There  are  no  specific  "school  diseases," 
but  a  number  of  diseases  are  especially  prevalent  during 
school  life;  among  these  are  especially  noteworthy  the  eye, 
mouth,  and  throat  diseases,  cardiac  diseases,  defects  in  spinal 
column,  infectious,  general,  and  skin  diseases. 

Infectious  catarrhal  conjunctivitis  is  a  disease  very  frequent 
among  school  children. 

Trachoma,  or  granular  conjunctivitis,  Ls  another  of  the  eye 
diseases  prevalent  among  school  children  of  the  poorer 
classes. 

Myopia  is  one  of  the  diseases  directly  due  to  school  life, 
to  study,  defective  light  and  illumination,  improper  position, 
faulty  seats  and  desks,  defective  methods  of  \\Titing,  faulty 
print,  and  eye  strain  generally.  Children  who  come  to  school 
with  some  degree  of  weak  vision  gradually  develop  increased 
myopia,  reaching  c{uite  a  high  degree  by  the  time  of  graduation. 
Thus,  in  New  York  schools  the  percentage  of  myopics  in 
lower  grade  8  was  8  per  cent.,  while  in  the  higher  grade  2  it 
was  20.2  per  cent. 

The  mouth,  nose,  and  throat  diseases  prevalent  among  school 
children  are  coryza,  adenoid  growths,  hj-pertrophied  tonsils, 
recurrent  tonsillitis,  habitual  nose  bleeding,  etc. 

The  cardiac  and  circulatory  diseases  are  anemia,  chlorosis, 
endocarditis,  etc. 

The  respiratory  diseases  most  frec[uent  in  school  life  are 
bronchitis,  bronchopneumonia,  and  pleurisy. 


70  SCHOOL  HYGIENE 

The  digestive  diseases  favored  by  school  Hfe  are  anorexia, 
constipation,  and  simple  gastritis  due  to  hurried  meals,  too 
short  time  for  lunches,  mental  worry  and  strain,  etc. 

The  skin  diseases  prevalent  are  scabies,  ringworm,  pedicu- 
losis, etc. 

The  nervous  diseases  especially  resulting  from  school  life 
are  chorea,  neurasthenia,  etc. 

Spinal  diseases  due  directly  to  school  conditions  are 
scoliosis,  k^^hosis,  and  lordosis  due  to  faulty  seats,  posi- 
tion, etc. 

Among  the  infectious  diseases  raging  in  school  are  especially 
noted  the  exanthemata,  the  spread  of  which  is  favored  by 
school  segregation,  also  diphtheria,  pertussis,  parotitis,  etc. 

Causes  of  the  Ill-efEects  of  Schools  on  Health. — The  etiological 
factors  to  which  the  pathological  conditions  referred  to  above 
are  due  are  very  numerous,  but  may  be  grouped  into  two 
broad  influences:  (1)  The  school  buildings  themselves,  and 
(2)  the  influence  of  the  studies. 

The  influence  of  the  school  buildings  and  arrangement  upon 
the  health  of  the  school  children  may  be  summarized  in  the 
following  conditions:  Defective  sites,  soil,  and  foundation; 
dampness  in  cellar  and  walls;  absence  of  fire  protection; 
insufiicient  natural  light,  defective  provisions  for  illumination, 
impure  air,  and  defective  provision  for  ventilation;  inadequate 
floor  and  cubic  space,  overcrowding,  congestion,  defective 
methods  of  heating,  plumbing,  and  cleaning;  all  the  above 
factors  of  defective  housing  will  influence  the  health  of  school 
children. 

Other  factors  adversely  influencing  school  children  may  be 
classified  as  follows: 

Personal^         Physical,  mental,  and  moral  defects  of  chil- 
dren previous  to  entering  school. 

Economics^     Poverty  of  parents. 

Ignorance  of  parents. 
Undernourishment  of  children. 

Studies.*  Too  early  school  age. 

Too  long  school  day. 
Overfatigue  and  lack  of  recesses. 


BEST  SITES  FOR  SCHOOLS  71 

Curriculum.     Multiplicity  of  subjects. 

DiflBcult  or  unnecessary  subjects  of  study. 

Improper  methods  of  study. 

Competition,  tests,  examinations. 
Teachers.        Personal  factors. 

Brutality,  ignorance,  and  carelessness. 

Discipline,  pmiishments,  etc. 

Most,  if  not  all,  the  harmful  effects  on  health  of  school 
children  may  be  traced  to  one  or  several  of  the  causes 
enumerated  above,  causes  which  are  important  as  bearing 
an  intimate  relation  to  child  and  public  health. 

Prophylaxis.  School  Hygiene.  —  The  preservation  and 
promotion  of  the  health  of  school  children,  and  the  prevention 
of  the  ill-effects  of  school  life  upon  health  may  be  accomplished 
(1)  by  the  sanitation  of  school  buildings,  and  (2)  by  rational 
methods  of  study  and  care  of  school  children. 

The  best  sites  for  schools  should  be  selected;  they  should 
be  dry,  porous,  well  drained,  free  on  all  sides,  distant  from 
any  buildings,  far  from  factories,  offensive  trade  establish- 
ments, markets,  boiler-shops,  saloons,  elevated  railroads,  etc., 
far  from  any  thing  creating  noise,  smoke,  smell,  gases,  or 
fumes. 

It  is  desirable  that  a  school  site  should  occupy  a  separate 
whole  block  near  a  public  park,  playground,  etc. 

The  most  modern  construction  of  sanitary  school  buildings 
should  be  employed,  and  there  should  not  be  penuriousness 
or  "economy''  in  this  regard. 

No  existing  structures  built  for  other  pm-poses  should  be 
reconstructed  or  made  over  for  schools,  but  school  buildings 
should  be  especially  constructed  for  their  purpose. 

No  school  house  except  in  the  poorest  rural  community, 
should  be  constructed  of  wood;  brick  and  stone  should  be  the 
materials  of  school  buildings,  and  in  large  cities  they  should 
be  constructed  of  fireproof  reinforced  concrete,  or  of  steel 
frames  with  stone  or  concrete. 

The  number  of  stories  in  school  houses  should  be  limited, 
and  no  matter  how  fireproof  a  building  may  be,  the  school 


72  SCHOOL  HYGIENE 

children  should  be  able  to  walk  up  to  the  upper  stories,  and  not 
be  compelled  to  use  elevators.  Four  or  five  stories  should  be 
the  limit  in  height. 

The  basement,  or  lower  story,  should  run  under  the  whole 
school  building,  should  be  high,  dry,  well  lighted,  and  venti- 
lated, and  may  be  used  for  workshops,  bathrooms,  machinery, 
etc.,  but  should  not  be  used  for  playground  or  gymnasium; 
these  latter  should  be  either  upon  the  school  grounds  or  upon 
the  roof. 

Large  entrance  and  exit  doors  should  be  provided  in  many 
places  and  on  every  floor;  the  stairways  should  be  broad,  light, 
and  fireproof. 

There  should  be  in  a  school  building  not  less  than  thirty 
square  feet  of  space  for  each  pupil,  so  that  a  school  constructed 
for  1000  children  should  contain  not  less  than  30,000  square 
feet  of  floor  space. 

There  should  be  a  limit  to  the  size  of  school  buildings, 
and  three  school  houses  for  10,000  children  are  better  than 
two,  or  one,  no  matter  how  large  and  spacious  this  last  one 
may  be. 

There  is  no  need  for  too  much  ornamentation  in  school 
architecture;  the  interiors  should  be  plain,  smooth,  junctions 
of  ceiling  and  floors  with  walls  be  concave,  and  all  projections, 
mouldings,  etc.,  where  dirt  and  dust  may  lodge,  be  elimin- 
ated. 

The  walls,  floors,  ceilings,  and  partitions  should  be  sound- 
proof, should  also  be  damp-,  fire-,  vermin-,  and  dust-proof. 

Solid  floors  of  reinforced  concrete  are  best  for  schools; 
the  top  of  floors  may  be  of  hard  wood  laid  in  a  narrow  strip  and 
well  oiled  or  waxed. 

The  inner  surfaces  of  walls  and  ceilings  should  be  finished 
smooth  and  colored  in  bright  tints. 

The  schoolroom  is  the  unit  of  the  school  house;  it  should 
be  oblong  in  shape,  about  30  by  25  feet,  and  not  less  than 
13  feet  in  height. 

Ample  provision  should  be  made  for  dressing  rooms, 
library,  study  rooms,  auditorium,  bathrooms,  teachers' 
rooms,  etc. 


SCHOOL  HOUSE  HEATING  73 

School  House  Lighting. — ^The  window  area  of  school  houses 
should  be  not  less  than  one  fourth  of  the  floor  space;  the  top 
of  windows  should  not  be  more  than  six  inches  from  the  ceilings; 
the  windows  should  be  square  on  top,  and  reach  to  about 
four  feet  from  floor;  the  piers  between  windows  should  be  as 
narrow  as  possible  and  bevel-edged,  the  panes  made  in  large 
dimensions  without  intervening  bars.  The  window  glass 
should  be  ribbed,  or  prism  glass. 

Schoolrooms  should  be  lighted  from  above,  wherever 
possible,  and  from  the  left  on  all  floors  where  light  cannot  be 
gotten  from  above. 

Window  roller  shades,  properly  adjusted,  may  be  necessary, 
but  should  be  avoided,  if  possible,  because  of  the  dust  they 
gather. 

For  artificial  illumination,  electric  lights  are  the  best,  and 
there  is  no  reason  why  in  all  larger  schools  this  form  of  illumi- 
nation should  not  be  used  exclusively,  as  it  is  the  best. 

School  House  Ventilation. — ^Theoretically  no  school  house 
should  rely  upon  natural  ventilation,  as  such  a  ventilation, 
even  with  addition  of  artificial  openings  is  not  sufficient  to 
provide  the  needed  air  and  to  make  the  exchange  of  air 
necessary  in  schools  with  large  numbers  of  pupils  in  class 
rooms;  while  the  opening  of  windows,  etc.,  is  objectionable 
on  account  of  the  cold,  noise,  and  dust  they  let  in.  Therefore, 
all  school  buildings  should  be  provided  with  mechanical 
ventilation,  with  a  combined  vacuum  and  plenum  system  of 
ventilation,  with  the  supply  of  air  carefully  regulated  as  to 
temperature,  quantity,  humidity,  and  purity. 

School  House  Heating. — Local  heating  is  obsolete  in  all 
except  small  village  schools.  A  central  heating  and  venti- 
lating plant  should  be  provided  for  all  large  schools.  Small 
schools  may  be  provided  with  a  central  hot-water  heating 
plant,  but  in  all  very  large  schools  the  indirect  system  of  heat- 
ing is  the  best,  as  it  combines  a  ratiorTal  system  of  heating 
with  ventilation.  This  systpm  consists  in  placing  the  heated 
steam  radiators  or  coils  in  a  separate  air  chamber,  from  where 
the  warmed  air  is  forced  by  proper  motors  and  fans  into 
the  ducts  leading  into  every  room,  where  they  end  in  inlets 


74  SCHOOL  HYGIENE 

in  appropriate  locations.  The  velocity  and  humidity  of  the 
incoming  air  may  thus  be  regulated,  and  the  air  may  also  be 
filtered  and  partly  purified. 

School  House  Water  Supply. — ^An  ample  supply  of  water  is 
needed  in  schools.  The  supply  fixtures  should  be  conveni- 
ently situated  so  as  not  to  necessitate  too  great  distances  to 
travel  for  obtaining  a  drink;  some  sanitary  individual  drink- 
ing cups  should  be  provided,  and  the  water  supplied  for 
drinking  purposes  should  invariably  be  filtered  through  a 
properly  adjusted  and  frequently  cleaned  filter. 

School  House  Plumbing. — There  should  be  an  ample  provi- 
sion for  wash  rooms,  basins,  shower  baths,  urinals,  water 
closets,  all  situated  conveniently,  in  well-lighted,  heated,  and 
ventilated  apartments;  the  fixtures  made  of  porcelain  or 
enamelled  iron,  the  floors,  walls,  and  ceilings  of  such  apart- 
ments constructed  of  stone,  tile,  or  pressed  glass.  Water  closets 
should  be  provided  with  automatic  flush  apparatus. 

School  House  Cleaning. — Daily,  weekly,  and  periodical  clean- 
ing of  schoolrooms  should  be  the  rule;  wet  methods  of  clean- 
ing should  invariably  be  used,  and,  whenever  possible,  a  com- 
plete system  of  vacuum  cleaning  installed. 

Indeed,  there  should  be  applied  to  all  parts  of  school  con- 
struction the  latest,  the  most  advanced,  and  modern  methods 
of  construction  and  equipment,  because  the  preservation 
and  promotion  of  the  health  of  the  next  generation  is  the 
corner-stone  of  public  health. 

School  Furniture. — ^The  school  furniture  bears  an  important 
relation  to  the  health  of  the  pupils. 

School  furniture  consists  of  desks,  seats,  platforms,  black- 
boards. Of  importance  also  are  the  books,  slates,  writing- 
paper,  and  pens  and  pencils. 

The  construction  and  arrangements  of  the  desks  and  seats 
are  of  great  importance  in  the  matter  of  position  and  attitude 
of  the  pupil.  Owing  to  the  variations  in  the  height  of  each 
pupil  the  desks  must  be  individual  and  adjustable,  so  as  not 
to  compel  him  to  assume  unnatural  attitudes  in  sitting  and 
writing,  to  prevent  formation  of  spinal  curvature;  the  distances 
of  the  desks  from  the  blackboard  should  be  adjusted  according 


ETIOLOGICAL  FACTORS  OF  SCHOOL  DANGERS      75 

to  the  strength  of  vision  of  each  pupil.  The  seats  and  desks 
should  therefore  be  adjustable  and  periodically  adjusted 
after  physical  examination  of  each  pupil. 

Desks  and  seats  as  well  as  teachers'  platforms  should  not 
be  permanently  attached  to  the  floor,  but  should  be  made 
removable. 

The  blackboards  should  be  so  placed  as  to  be  visible  to  all 
pupils,  and  the  writing  upon  them  should  be  so  large  and 
distinct  as  to  be  \isible  without  strain  by  the  pupils  in  the 
rear  seats. 

Slate  blackboards  are  preferable  to  wood,  but  the  writing 
upon  same  with  chalk  producing  large  quantities  of  dust  is 
not  sanitary,  and  should  be  replaced  by  some  improved 
method.  In  some  schools  manila  paper  of  proper  shades  with 
writing  painted  with  brush  has  been  substituted  for  slate  and 
chalk. 

The  books  used  in  schools  should  be  printed  in  large  types, 
and  should  be  disinfected  at  stated  intervals. 

Pictures,  charts,  globes,  models,  instruments,  etc.,  should 
be  coated  with  varnish,  be  smooth  and  easily  cleaned. 

The  correction  of  the  other  etiological  factors  of  school 
dangers  to  health  may  be  summed  up  in  the  following  measures : 
(1)  Counteraction  of  injurious  home  influences;  (2)  care  for 
the  proper  feeding  of  school  children;  (3)  regulation  of  school 
hours,  pauses,  rest,  etc. ;  (4)  a  rational  method  and  system  of 
study;  (5)  education  of  a  proper  teaching  staff;  (6)  prevention 
of  overcrowding,  congestion,  etc.;  (7)  promotion  of  health 
and  vital  resistance;  (8)  isolation  of  the  physical,  mental, 
and  moral  defectives;  (9)  prevention  of  the  spread  of  infectious 
diseases;  (10)  proper  medical  school  supervision. 

If  the  school  is  to  have  a  lasting  and  thorough  influence 
upon  the  physical,  mental,  and  moral  well-being  of  the  next 
generation,  the  school  child  should  be  the  ward  of  the  State, 
at  least  in  so  much  as  the  supervision  of  the  home  influences 
are  concerned.  Whether  due  to  alcoholism,  brutality, 
ignorance,  or  poverty,  subversive  home  influences  should  be 
counteracted  by  the  school,  so  that  the  child  does  not  lose  at 
home  what  it  gains  in  health  and  mental  and  moral  develop- 


76  SCHOOL  HYGIENE 

ment  in  school.  Whether  the  school  authorities,  or  a  separate 
branch  of  the  education  department,  whether  through  lectures 
and  popular  education  of  parents,  or  through  the  aid  of  visit- 
ing nurses  to  the  homes,  or  by  some  other  means  as  yet  not 
devised,  the  harmful  home  influences  upon  children  should 
be  controlled  and  counteracted. 

A  most  important  prophylactic  measure,  and  a  step  of 
paramount  value  in  the  preservation  and  promotion  of  the 
health  of  school  children  is  their  proper  feeding. 

It  is  a  universal  dictum  that  no  healthy  mind  can  exist  in  an 
unhealthy  body,  and  that  a  body  cannot  be  healthy  if  it  is  not 
properly  or  sufficiently  fed. 

Whether  it  is  due  to  ignorance  of  the  parents,  or,  what  is 
more  true,  to  poverty,  as  has  been  lately  proved  in  the  case 
of  the  school  children  of  many  large  cities,  a  great  many  school 
children  come  to  school  hungry  and  stay  hungry  during  the 
day.  That  neither  physical  nor  mental  development  is 
possible  under  such  conditions  is  self-evident,  and  no  rational 
system  of  education  can  afford  to  neglect  this  important  factor. 

Wliether  all  school  children,  or  those  only  who  apply, 
should  be  fed;  whether  such  feeding  should  be  absolutely /ree, 
or  paid  for  by  a  nominal  sum;  whether  it  should  be  done  by 
private,  public,  or  school  authorities;  whether  breakfasts  and 
lunches,  or  but  one  meal,  should  be  furnished,  are  all  ques- 
tions for  the  social  economists  to  decide.  On  the  part  of 
hygiene  the  demand  is  only  made  that  the  school  child  should 
be  properly  fed  and  nourished.  Nor  does  it  deter  the  sani- 
tarian from  such  demand,  that  the  argument  is  advanced 
that  feeding  of  children  by  the  State  may  lead  to  the  demand 
to  have  them  clothed,  shoed,  furnished  with  eyeglasses,  etc. 

School  Age  and  Hours. — ^The  regulation  of  the  age  of  entrance 
to  schools,  the  regulation  of  the  length  of  school  day,  the 
recesses,  prevention  of  overfatigue,  etc.,  are  matters  of  impor- 
tance. 

The  points  upon  which  educators  and  sanitarians  seem  fo 
have  agreed  are  as  follows: 

That  no  child  should  be  made  to  attend  school  before  the 
age  of  six,  or,  better,  seven,  and,  if  in  delicate  health,  later. 


SCHOOL  AGE  AND  HOURS  77 

That  younger  children  from  five  to  seven  years  of  age  may 
attend  kindergartens,  provided  their  stay  indoors  is  limited,  and 
the  close  needlework,  etc.,  requiring  eye  strain  are  eliminated. 

That  the  length  of  the  school  day  be  graded  to  the  age,  sex, 
grade  of  study,  physical  condition,  and  mental  state  of  each 
pupil;  that  recesses  should  be  had  after  every  forty-five 
minutes  of  study  in  the  higher  grades  and  thirty  minutes  in 
the  lower  grades,  with  pauses  of  ten  minutes  in  the  lower 
and  fifteen  minutes  in  the  higher  grades. 

That  mid-day  recesses,  wherever  there  is  an  afternoon 
session,  should  be  longer  than  commonly  allowed,  and  that 
serious  studies,  or  those  requiring  mental  strain,  be  not  pur- 
sued afternoons. 

That  the  current  multiplicity  of  studies  be  substituted  by  the 
most  important  and  useful  subjects,  and  that  education  should 
fit  the  child  for  the  struggle  of  existence  in  the  world,  instead 
of  filling  his  head  with  useless  knowledge  to  be  soon  forgotten. 

That  dead  languages  and  abstruse  subjects  should  be 
made  electives  to  older  children  with  special  abilities  or 
desires  for  scientific  vocations. 

That  methods  of  study  be  made  more  inductive,  experi- 
mental, and  objective;  that  less  attention  be  pain  to  definitions, 
dates,  and  figures;  and  that  the  efficiency  of  the  pupil  be 
gauged  not  upon  lucky  answers  in  periodical  tests  and  exami- 
nation, but  on  progress  during  the  entire  year. 

That  home  work,  examinations,  and  competitive  trials,  so 
injurious  to  health,  be  abolished,  or,  at  least,  eliminated  as 
much  as  possible. 

That  defectives  physically,  mentally,  or  morally  should  not 
be  left  with  the  other  pupils,  but  should  be  segregated  and 
taken  care  of  by  special  instructors. 

For  the  introduction  of  an  ideal  hygienic  system  of  teaching 
it  is  no  less  necessary  that  there  be  trained  a  specially  fitted 
corps  of  tutors,  sympathetic,  earnest,  devoted  to  their  duty, 
permanent,  well  paid,  and  secured  against  changes  in  com- 
plexion of  educational  boards,  and  that  a  teaching  staff  who 
look  upon  their  work  as  a  transitory  occupation,  or  stepping- 
stone  to  marriage,  be  eliminated. 


78  SCHOOL  HYGIENE 

The  overcrowding  of  pupils  in  classes,  the  placing  of  fifty 
or  sixty  pupils  in  one  schoolroom,  is  a  disgrace  to  the  munici- 
pality tolerating  it,  a  torture  to  the  teaching  staff,  and  a  menace 
to  the  health  of  the  children. 

Classes  of  over  twenty-five  are  difficult  to  handle,  and  over 
forty  impossible  to  control;  the  teacher's  time  should  not  be 
occupied  in  matters  of  discipline,  but  in  the  mental  develop- 
ment of  the  pupils,  and  this  is  impossible  if  the  teacher  cannot 
have  a  personal  acquaintance  with,  and  control  of,  each  pupil. 

The  promotion  of  the  health  of  the  school  children  may  be 
furthered  by  a  rational  system  of  playgrounds,  gymnastics, 
physical  exercise,  bathing,  swimming,  etc. 

All  physical  exercises  and  sports  should  be  under  the  super- 
vision and  control  of  a  medical  instructor,  and  all  pupils 
suffering  from  congenital  or  acquired  cardiac  trouble  should 
be  excluded  from  the  general  classes  in  such  subjects. 

As  an  aid  for  the  promotion  of  health  the  educational 
system  should  provide  in  every  class  and  grade  of  school  study 
and  teaching  in  personal  hygiene,  and  of  public  hygiene  in 
the  higher  classes. 

The  control  of  the  sanitation  of  schools,  of  the  health  of 
school  children,  of  the  preservation  of  their  physical  bodies, 
and  the  prevention  of  constitutional  and  infectious  diseases 
should  be  made  the  duty  of  a  rational  system  of  medical 
school  supervision. 

A  medical  supervision  of  schools  that  should  be  efficient 
can  only  be  accomplished  by  the  appointment  of  reliable, 
permanent,  competent,  well-paid  physicians,  who  should  be 
permanently  and  completely  attached  to  the  school  and  be  a 
part  of  the  educational  staff,  who  should  be  debarred  from 
outside  practice,  and  there  should  not  be  more  than  500 
pupils  under  the  supervision  of  each. 

A  rational  system  of  medical  school  supervision  would  also 
embrace  the  appointment  of  oculists,  dentists,  nose  and  throat 
specialists,  teachers  of  hygiene,  and  visiting  nurses. 

Some  of  the  duties  of  medical  inspectors  of  schools  would 
be:  (1)  Physical  examination  of  pupils  entering  school;  (2) 
annual  thorough  physical  examination.   (3)  daily  physical 


QUESTIONS  79 

inspection;  (4)  isolation  of  suspected  ca.'ies;  (5)  removal  and 
quarantine  of  contagious  cases;  (6)  supervision  of  physical 
exercises  of  pupils;  (7)  treatment  of  physical  and  mental 
defectives;  (8)  prevention  of  correctible  defects;  (9)  teaching 
of  hygiene  to  pupils  and  teachers;  (10)  sanitary  supervision 
and  inspection  of  school  house,  rooms,  desks,  seats,  etc.; 
(llj  adjusting  of  desks  and  seats  according  to  groTV'th,  height, 
ind  eyesight  of  each  pupil;  (12)  the  systematic  supervision, 
study,  care,  and  control  of  the  health  of  the  school  children. 

^Miile  such  an  outline  scheme  of  medical  school  supervision 
is  as  yet  not  introduced  in  its  entirety  in  modern  schools, 
there  are  clear  indications  that  it  is  bound  to  come  in  time, 
and,  when  it  does  come,  will  certainly  be  a  great  sanitary 
advance  and  a  powerful  means  for  the  promotion  of  public 
health. 

QUESTIONS. 

■What  are  the  effects  of  schools  upon  the  health  of  pupils? 

What  special  diseases  are  favored  by  school  hfe? 

WTiat  are  the  so-called  "school  diseases?" 

WTiat  are  the  effects  of  schooLs  upon  the  eyes  of  children  ? 

T\Tiat  are  the  effects  of  schools  upon  the  nervous  system? 

Wliat  role  do  schools  play  in  the  dissemination  of  infectious  diseases? 

WTiat  are  the  principal  conditions  of  school  hfe  adversely  affecting  school 
children  ? 

Describe  the  proper  construction,  lighting,  warming,  ventilation,  and 
plumbing  of  school  houses. 

TMiat  are  the  sanitars'  requirements  of  school  furniture  and  utensils? 

TSTiat  are  the  hygienic  requirements  of  the  school  curriculum? 

Wh.at  are  the  aims  and  purposes  of  medical  school  inspection? 

What  are  the  essential  features  of  a  modem  school  inspection  sj'stem? 


CHAPTER  IV. 

INDUSTRIAL  HYGIENE. 

OCCUPATION  AND  HEALTH. 

r  Industrial  hygiene  is  the  branch  of  pubHc  hygiene  which 
deals  with  the  relation  of  occupations  to  health,  with  the  effect 
of  industries  upon  the  workers;  with  the  preservation  and 
promotion  of  the  public  health  by  eliminating  the  adverse 
causes  incident  to  industries,  and  with  the  prolongation  of  the 
life  of  workers  by  improving  the  conditions  under  which  they 
work  and  live. 

The  relation  of  occupation  to  health  is  a  very  intimate 
one,  and  occupation  is  one  of  the  most  important  factors  of 
environmental  life  influencing  public  health,  mortality  and 
morbidity. 

This  claim  is  substantiated  by  the  fact  that  the  whole 
population,  with  the  exception  of  the  too  old  or  too  young, 
is  engaged  in  some  gainful  occupation,  in  which  from  one-  to 
two-thirds  of  life  are  spent;  that  certain  dangers  to  life,  limb, 
and  health  are  known  to  be  due  directly  to  certain  occupa- 
tions, and  that  certain  industries  are  known  to  cause  directly, 
or  indirectly,  certain  pathological  conditions,  which  are  fatal 
to  life. 

r    Facts  from  ample  statistical  data  show  that : 

1.  The  mortality  of  workers  in  certain  industries  is  greater 
than  that  of  workers  in  other  industries. 

2.  That  certain  industries  show  a  persistently  larger 
mortality  from  certain  diseases  than  others. 

3.  That  certain  occupations  show  a  persistently  greater 
number  of  fatal  and  non-fatal  accidents  than  others. 

4.  That  these  figures  are  true  in  ^■arious  countries  and 
periods. 

(80) 


OCCUPATION  AND  HEALTH  81 

5.  That  the  mortahty  and  morbidity  of  workers  is  greater 
whenever  there  are  in  the  industries  certain  elements  known 
to  be  dangerous  to  health  and  life. 

The  effects  of  industries  on  health  may  be  summed  up  in  the 
following : 

1.  Sudden  death  due  to  accidents,  falls,  burns,  explosions, 
etc. 

2.  Total  or  partial  disability  from  the  same  causes. 

3.  Sudden  deaths  from  acute  intoxications  by  poisons, 
fumes,  and  gases. 

4.  Deaths  from  chronic  intoxications  by  the  same  elements. 

5.  Deaths  due  to  infectious  material  in  industries. 

6.  Diseases  due  to  direct  action  of  dangerous  elements  in 
trades. 

7.  Diseases  due  indirectly  to  industries  and  occupations. 
The  causes  of  the  ill-effects  of  industries  on  life  and  health 

are  due  to  a  large  number  of  factors,  which  must  be  considered 
separately  and  individually. 

The  etiological  factors  playing  an  important  role  in  the 
causation  of  industrial  diseases  and  occupation  mortality 
may  be  stated  as  follows : 

Group  I. — Adverse  conditions  due  to  personal  factors: 

Personal  health  of  worker. 

Susceptibility,  vitality,  and  resistance. 

Nutrition  and  personal  hygiene. 

Ignorance,  carelessness,  etc. 

Choice  of  trade. 

Sex. 

Age. 
Group  II. — Adverse  conditions  due  to  place  of  work: 

Outdoor  and  indoor  work. 

Surface  and  subsurface  work. 

Factory,  workshop,  and  homework. 

Factory  sanitation. 
Group  III. — Adverse  conditions  in  the  industries  themselves: 

Active  and  sedentary  work. 

Extremes  of  climate. 

Light,  temperature,  and  humidity. 

6 


82  INDUSTRIAL  HYGIENE 

Air  pressure. 
Attitude  and  position. 
'  Duration  and  pauses. 
Fatigue. 

Tension,  worry,  and  responsibility. 
Insecure  tenure,  etc. 
Wages  and  compensation. 
Group  IV. — Adverse  conditions  due  to  materials  and  pro- 
cesses. 

Dust. 

Poisons. 

Gases  and  fumes » 

Infectious  material. 

Hazards  and  accidents, 

A  brief  review  of  the  above  various  adverse  factors  is 
necessary  in  order  to  understand  the  principles  of  prevention 
of  industrial  diseases. 


PERSONAL  FACTORS. 

The  individual  health  and  the  normal  physical  development 
of  the  individual  worker  are  of  prime  importance  in  the  in- 
fluence of  industry  upon  health.  The  greater  the  sum  of 
health  the  worker  starts  out  with  at  the  beginning  of  his 
career  the  more  efficient  will  be  his  work,  and  the  less  he 
will  be  liable  to  suffer  from  the  adverse  conditions  incident  to 
his  work. 

The  susceptibility  and  vital  resistance  partly  depend  on 
the  physical  health  of  the  worker,  and  partly  on  individual 
idiosyncrasies.  Thus  there  are  certain  persons  who  seem  to 
be  less  susceptible  to  certain  poisons  than  others;  and  there 
are  many  who  evidently  enjoy  a  certain  immunity  against 
the  effects  of  poisons  and  infections  to  which  others  very 
quickly  succumb. 

Personal  Hygiene. — The  nutrition,  housing,  clothing,  and 
habits  play  an  important   role  in  the  ability  of  workers  to 


PERSONAL  FACTORS  83 

resist  the  adverse  influences  of  certain  industries.  A  faulty  or 
inadequate  nutrition,  indulgence  in  alcohol  or  drugs,  improper 
or  insufficient  clothing,  defective  insanitary  housing,  and  other 
unhygienic  personal  factors  reduce  the  health  of  the  individual, 
lessen  his  vital  resistance  and  make  him  a  fitter  subject  to 
be  influenced  by  any  and  all  adverse  conditions  incident  to 
industrial  life. 

Ignorance,  bravado,  and  carelessness  have  an  important  share 
in  the  etiology  of  accidents  to  which  so  many  deaths  are  due. 

The  choice  of  trade,  while  in  a  large  number  of  cases  deter- 
mined by  natural  selection,  is  due  in  the  majority  of  cases  to 
chance  and  personal  whim,  although  it  is  of  the  utmost  impor- 
tance to  the  health  of  the  worker,  for  upon  the  right  choice  of 
occupation  depend  not  only  his  efficiency  but  also  his  health 
and  length  of  life. 

A  feeble  individual  selecting  a  strenuous  trade  because  of 
its  larger  emoluments;  a  congenital  cardiac  defective  selecting 
caisson  work,  etc.,  will  soon  succumb  to  the  effects  of  trade, 
whereas  he  might  have  lived  much  longer  had  he  selected  an 
occupation  equal  to  his  physical  power.  The  same  applies 
to  phthisically  inclined  individuals  selecting  a  dusty  occupa- 
tion, etc. 

Sex. — ^The  injurious  effects  of  industry  upon  women  are 
due  to  the  following  factors: 

1.  The  comparative  greater  physical  weakness  of  women. 

2.  The  greater  disposition  to  toxic  influences. 

3.  The  effects  of  labor  upon  the  reproductive  organs. 

4.  The  periodical  semipathological  state  of  women. 

5.  The  effects  upon  offspring. 

6.  The  effect  upon  children  and  home. 

Physical  Strength  of  Women. — While  women,  as  a  rule, 
choose  trades  requiring  little  physical  effort,  the  length  of 
work  and  the  conditions  under  which  it  is  carried  on  are  too 
strenuous  for  them. 

It  is  well  known  that  women's  susceptibility  to  industrial 
poisons  is  greater  than  men's.  Especially  is  this  the  case  with 
lead,  mercury,  and  phosphorus.  There  are  ample  statistical 
data  showing  the  immensely  greater  proportion  of  deaths 


84  INDUSTRIAL  HYGIENE 

from  industrial  poisons  among  women  as  compared  with  men. 
workers. 

Certain  conditions  of  work  in  women:  sitting,  prolonged 
standing,  work  on  sewing  machines,  etc.,  are  known  to  be 
the  cause  of  congestion  of  uterus  and  appendages,  malposi- 
tions, and  chronic  inflammations. 

The  semipathological  state  in  which  women  find  themselves 
during  several  days  in  each  month  are  prolific  causes  of  the 
harmful  influences  of  industries  upon  the  women  compelled 
to  work  during  these  periods.  The  natural  congestion  of 
the  reproductive  organs  during  these  periods  is  increased  by 
certain  work,  and  is  bound  to  become  injurious  to  health. 

The  effects  of  industrial  life  on  the  offspring  are  seen  in  the 
appalling  infant  mortality  and  large  abortion  and  miscarriage 
rates  prevalent  in  all  industrial  towns.  Abortions  and  miscar- 
riages are  due  to  the  hard  work  during  the  later  periods  of 
pregnancy,  and  especially  to  the  effects  of  certain  poisons. 
Thus,  according  to  Tardieu,  out  of  one  thousand  pregnancies 
among  female  lead  workers  there  were  not  less  than  609 
abortions.  Miscarriages  and  abortions  among  female 
workers  are  also  caused  by  the  continuous  labor  and  too 
heavy  tasks  performed  by  them. 

Effects  on  the  Home  of  Working  Women. — ^The  large  rate  of 
infant  mortality  among  the  working  classes  is  sXsb  due  to  the 
lack  of  care,  the  artificial  feeding,  and  neglect  of  the  children 
by  their  working  mothers.  To  the  same  causes  are  also  due 
the  neglect  of  the  health,  proper  preparation  of  food,  and  care 
of  the  male  workers  of  the  family,  the  neglect  of  home,  etc. 

Age. — According  to  the  United  States  Census  there  are 
nearly  2,000,000  children  under  the  age  of  sixteen  employed 
in  various  occupations,  as  follows: 

Textile  industries 80,000  • 

Mines  and  quarries 25,000 

Tobacco  and  cigars 12,000 

Glass  industry 7,116 

Wood  industries 10,000 

Laundries 7,000 

Bakeries 2,000 

Stores 20,000 

As  servants,  waiters,  etc 138,000 

As  messengers 60,000 


PLACE  AND  CONDITIONS  OF  WORK  AND  HEALTH     85 

Baneful  as  are  the  effects  of  industrial  life  upon  women, 
they  are  still  more  so  upon  childpen. 

The  injurious  effects  of  labor  on  children  may  be  summed 
up  as  follows: 

Injury  to  the  weaker  organism. 

Interference  with  growth  and  physical  development. 

Production  of  spinal  and  bone  deformities. 

Production  of  pathological  conditions  predisposing  to  cer- 
tain diseases  of  early  and  late  life. 

The  stunting  of  mental  and  moral  development. 

Physical,  mental,  and  moral  degeneration. 

Shortening  of  life. 

The  effects  of  industrial  dust,  poison,  etc.,  is  comparatively 
greater  on  children  than  on  adults,  and  the  relative  number 
of  all  industrial  accidents  is  greater  among  children  workers 
than  adults. 

Undoubtedly  child  labor,  if  very  extensive  and  if  persistent 
and  prevalent,  is  bound  to  produce  a  debilitated  generation, 
and  be  of  the  greatest  influence  in  the  physical  deterioration 
of  the  race. 


THE  PLACE  AND  CONDITIONS  OF  WORK  AND  HEALTH. 

The  place  where  the  work  is  carried  on  influences  the 
workers'  health. 

The  morbidity  and  mortality  of  workers  differ  according 
as  the  labor  is  indoor  work  or  outdoor  work. 

This  is  undoubtedly  due  to  the  difference  in  the  purity  of 
air,  to  the  lesser  fatigue  felt  by  outdoor  workers,  and  in 
the  decrease  in  the  liability  to  respiratory  diseases  and 
mortality  from  tuberculous  diseases  which  outdoor  workers 
enjoy. 

The  following  figures  from  Ogle  are  often  quoted  in  proof 
of  the  advantages  of  outdoor  work: 


86  INDUSTRIAL  HYGIENE 

MoETALiTY  Rate  of  Adult  Males  between  the  Ages  of  Forty-five 

AND  Sixty-five  from  Tuberculosis  and  Respiratory  Diseases, 

taking  the  Death  Rate  of  Fishers  as  a  Standard,  100. 

Other 
Tuber-   respiratory 
culosis.     diseases.        Total, 

c  Fishers     .....  55  45  100 

Outdoor  workers  <  Gardeners      ....  61  56  117 

l  Agricultural  laborers     .  62  79  141 

(  Storekeepers         ...  84  59  143 

Indoor  workers    -j  Drapers 152  65  217 

I.  Printers 233  84  317 

Subsurface  location  of  work  is  more  unhealthy  than  work 
carried  on  upon  the  surface,  other  things  being  equal. 

Thus,  tunnel  workers,  miners,  and  all  workers  underground 
not  only  are  liable  to  greater  dangers  from  accidents,  explo- 
sions, etc.,  but  also  suffer  from  absence  of  light,  fresh  air, 
great  heat,  accumulation  of  gases,  constrained  attitudes,  etc. 

The  greatest  danger  of  subsurface  workers  is  from  the  effect 
of  increased  air  pressure,  as  will  be  alluded  to  later. 

The  adverse  effects  of  home  work,  or  "sweat-shop"  work, 
are  partly  due  to  the  insanitary  conditions  under  which  home 
workers  are  compelled  to  work,  and  partly  to  other  causes, 
such  as  the  tendency  in  home  work  of  participation  by  the 
women  and  children  of  the  family;  the  longer  periods  of  work, 
the  dangers  of  infecting  the  children  by  the  dust  or  infective 
materials  carried  upon  work  (as  in  hides,  fur,  tobacco);  and  by 
the  added  danger  of  spreading  infection  from  the  house  (scarlet 
fever,  diphtheria,  tuberculosis,  etc.)  by  the  infected  garments 
or  work  materials.  Sweat-shop  workers  are  also  the  worst 
paid,  and  their  health  is  below  the  average  factory  workers. 

Factories  and  Workshops. — ^The  effects  of  workshops  and 
factories  upon  the  health  of  the  workers  depend  on  the  proper 
construction,  the  soil  and  site,  the  dampness  of  foundation 
and  walls,  insufficienct  light  and  illumination,  inadequate 
ventilation,  improper  heating,  faulty  drainage  and  plumbing, 
and  the  general  insanitary  conditions  of  the  premises. 

The  above  factors  are  not  peculiar  to  industrial  establish- 
ments alone,  but  they  have  greater  influence  on  the  health 
of  the  workers,  because  of  the  abnormal  conditions  in  which 
the  latter  are  placed  during  their  work. 


ADVERSE  INDUSTRIAL  CONDITIONS  87 


ADVERSE  INDUSTRIAL  CONDITIONS. 

Besides  the  personal  factors  and  the  influence  of  the  place 
of  work,  there  are  in  many  if  not  most  industrial  occupa- 
tions certain  abnormal  conditions  which  cannot  fail  of  having 
a  deleterious  influence  upon  the  health  of  the  workers. 
These  are  chiefly  those  described  in  the  following  paragraphs : 

Active  and  Sedentary  Occupations. — As  a  rule,  those  occupa- 
tions which  require  sedentary  postures  show  greater  liability 
of  their  workers  to  respiratory  and  tuberculous  diseases,  and 
the  morbidity  and  mortality  of  such  workers  is  greater  than 
that  of  workers  engaged  in  active  occupations. 

Statistical  data  clearly  show  the  greater  mortality  of  clerks, 
bookkeepers,  copyists,  typewriters,  stenographers,  engravers, 
tailors,  shoemakers,  seamstresses,  etc. 

A  constant  sitting  posture  at  work  presupposes,  as  a  rule, 
lack  of  muscular  action,  bent  body,  compressed  chest,  defi- 
cient metabolism,  and  lack  of  proper  oxygenation  of  the  blood 
It  is,  as  a  tule,  followed  by  anemia,  anorexia,  constipation, 
gastric  catarrh,  torpid  liver,  hemorrhoids,  venous  stasis,  low 
vitality,  tendency  to  respiratory  diseases,  especially  pulmo- 
nary tuberculosis. 

These  effects  are  more  pronounced  on  women,  children, 
and  adults  between  the  ages  of  fifteen  and  forty-five.  After 
the  latter  age  sedentary  occupations  are  not  so  harmful. 

Extremes  in  Climate  and  Temperatures. — Exposure  to 
extremely  cold  or  extremely  hot  climates  are  not  followed  by 
bad  effects  if  the  health  of  the  workers  is  good,  if  they  are 
clothed  and  fed  properly,  and  if  the  change  from  one  climate 
to  another  is  not  too  sudden.  Thus,  arctic  explorers  seem  not 
to  suffer  much  from  the  cold,  apart  from  occasional  frostbites, 
etc.  Hot  climates  seem  to  be  more  dangerous  than  very  cold; 
thus,  soldiers,  sailors,  and  workers  in  tropical  countries  seem 
to  suffer  from  debility,  anemia,  are  subject  to  special  tropical 
diseases,  and  the  rate  of  mortality  among  them  is  higher. 

Artificial  high  temperatures  are  prevalent  in  many  indus- 
tries. 


88  INDUSTRIAL  HYGIENE 

Bakers,  cooks,  blacksmiths,  firemen,  stokers,  furnacemen, 
blast-furnace  workers,  glass,  sugar  refinery  workers,  glass 
blowers,  electric  welders,  Turkish-bath  attendants,  miners, 
and  many  others  are  subject  to  and  are  affected  by  high 
temperatures. 

The  general  effects  of  too  high  temperatures  on  workers 
are  excessive  perspiration,  chills,  thickening  of  blood  plasma, 
tendency  to  respiratory  and  circulatory  diseases,  to  affections 
of  the  eyes  and  skin,  to  rheumatism,  tuberculosis,  etc. 

Light. — Insufficient,  improper,  and  inadequate  light  and 
illumination  of  workshops  cause  eye  strain,  headaches,  and 
eye  defects.  A  too  glaring  light  is  injurious  to  the  eyes, 
causes  inflammations,  predisposes  to  cataract  formation,  and 
other  eye  diseases.  Workers  who  are  exposed  to  such  condi- 
tions are  blast-furnace  and  glass  workers,  engineers,  electric 
workers,  stokers,  and  others. 

Humidity. — ^A  too  moist  air  is  injurious  to  health  by  inter- 
ference with  perspiration,  by  overheating  and  difficulty  in 
respiration.  Constant  work  in  an  air  which  has  a  high  rela- 
tive humidity  predisposes  to  rheumatic  and  respiratory 
affections,  and  is  dangerous  to  those  phthisically  inclined. 

Workers  in  textile  factories  are  especially  subjected  to 
very  moist  air,  it  being  the  practice  to  keep  the  relative 
humidity  of  the  air  in  such  factories  very  high  for  the  better 
conditioning  of  the  thread. 

Position  and  Attitude. — The  position  maintained  during 
work  is  not  without  its  influence  on  health. 

Salesmen  and  all  who  constantly  stand  on  their  feet  at 
work  often  suffer  from  varicose  veins,  hemorrhoids;  the 
women  from  congestions  of  the  pelvic  organs. 
,  The  constrained  attitudes  which  engravers,  draughtsmen, 
copyists,  shoemakers,  tailors,  etc.,  are  compelled  to  assume 
may  cause  defective  development  of  the  chest  in  younger 
workers,  a  stooping  habit,  narrow  chest,  defective  oxygena- 
tion, and  tendency  to  respiratory  diseases.  The  constrained 
attitude  which  some  coal  miners  are  compelled  to  assume 
while  "kirking,"  or  undercutting  seams,  have  been  referred 
to  as  causing  nystagmus. 


ADVERSE  INDUSTRIAL  CONDITIONS  89 

Air  Pressure. — ^There  are  a  number  of  industries  which  have 
to  be  carried  on  under  lesser  or  greater  air  pressure  than  the 
ordinary  air  pressure  of  fifteen  pounds  to  the  square  inch  to 
which  we  are  subjected  on  the  earth's  surface. 

Industries  Avith  decreased  air  pressure  are  exemplified  by 
mountain  climbers,  aeronauts,  bridge  workers. 

Industries  with  increased  air  pressure  comprise,  for  example, 
caisson  workers,  tunnel  workers,  divers,  pearl  seekers,  etc. 

The  effects  of  diminished  air  pressure  are  very  marked,  and 
often  fatal.  Rarefied  air  seems  to  be  especially  dangerous 
to  those  suffering  from  cardiac  disease. 

Results  of  Increased  Air  Pressure. — Caisson  Disease. — This 
term  is  applied  to  a  group  of  symptoms  the  pathology  of 
which  has  not  as  yet  been  fully  determined  and  agreed  upon, 
but  which  are  distinct  and  characteristic  of  workers  in  com- 
pressed-air chambers  with  air  pressures  two  or  three  times 
greater  than  the  ordinary. 

The  symptoms  appear  not  on  compression,  but  on  decom- 
pression; that  is,  on  the  removal  of  the  workers  from  the  com- 
pressed-air chambers.  The  symptoms  are  pain  in  the  ears, 
severe  cramps — "bends" — in  the  joints  and  muscles,  nose 
bleeding,  vertigo,  vomiting,  temporary  or  permanent  par- 
alysis of  the  lower  extremities,  unconsciousness,  and,  not 
infrequently,  sudden  death. 

Not  all  workers  seem  to  suffer  equally;  the  less  normal  in 
health  a  worker  is  the  more  quicldyhe  succumbs  to  "bends;" 
in  most  cases  the  effects  are  noted  only  when  the  pressure  is 
at  least  forty-five  pounds. 

According  to  Oliver,  "caisson  disease"  is  not  so  much  the 
result  of  a  toxemia  as  of  a  "sudden  liberation  of  gas  and  the 
presence  of  air  emboli  in  the  blood,  rupture  of  capillary  vessels, 
and  the  presence  of  free  air  and  blood  in  the  tissues." 

Fatigue. — Fatigue  is  a  condition  of  lowered  vitality  with 
an  accumulation  of  waste  products  in  the  body  and  formation 
of  special  toxins,  due  to  faulty  metabolism,  lack  of  vital 
resistance,  overwork,  violent  exercise,  tension,  strain,  etc.^ 
and  frequently  found  in  all  workers  who  have  to  undergo 
arduous  labor,  physical  or  mental  strain. 


90  INDUSTRIAL  HYGIENE 

Fatigue  is  a  purely  personal  factor,  and  depends  on  indi- 
vidual idiosyncrasy  and  susceptibility.  A  work  that  may 
cause  fatigue  symptoms  in  one  worker  may  not  produce  it  in 
another,  and  the  same  individual  is  more  subject  to  it  at  one 
time  that  at  another. 

Fatigue  is  also  influenced  by  environmental  factors,  or  the 
various  conditions  by  which  the  work  is  attended;  but,  as  a 
rule,  other  things  being  equal,  the  harder  the  work  the  more 
prolonged,  the  greater  the  strain,  the  velocity  of  the  work,  etc., 
the  sooner  and  greater  the  fatigue. 

General  fatigue  manifests  itself  in  a  diminished  vitality, 
in  a  lessened  resistance,  in  a  disability  to  perform  the  same 
amount  and  character  of  work,  and  a  predisposition  to  suc- 
cumb to  any  detrimental  influences  and  diseases. 

The  overworking,  or  too  prolonged  use  of  one  part  of  the 
body,  or  one  set  of  muscles,  or  one  organ,  is  often  followed 
by  "fatigue  neuroses,"  which  manifest  themselves  in  loss  of 
motor,  sometimes  of  sensory,  functions  of  the  particular  organ 
or  set  of  muscles.  General  fatigue,  alcoholism,  general 
weakness  of  the  organism  predispose  to  "fatigue  neuroses." 

The  most  common  example  of  such  neuroses  is  seen  in 
the  so-called  "writer's  cramp,"  a  convulsive  affection  of  the 
fingers,  loss  of  power  of  co5rdination  noted  in  some  writers, 
copyists,  and  others.  A  similar  affection  is  met  among  milk- 
men, typesetters,  telegraphers,  cigar  makers,  violinists,  etc. 

The  duration  of  work  is  a  potent  factor  in  the  effects  of  work 
on  health.  The  standard  of  normal  activity  differs  with  the 
individual  worker,  the  place  and  conditions  of  the  work.  But 
a  too  prolonged  daywork,  or  work  too  prolonged,  is  bound  to 
cause  fatigue  and  cause  the  body  to  be  in  a  state  extremely  liable 
to  be  influenced  by  any  untoward  causes  and  become  a  prey 
to  disease  and  infections. 

The  pauses  in  work  are  also  not  without  influence,  because 
of  the  necessity  for  the  recuperation  of  the  body  forces  after 
continuous  work.  As  much,  if  not  more,  work  may  be  accom- 
plished during  ten  hours  with  several  pauses  than  with  no 
pause  at  all.  Longer  pauses  than  those  commonly  allowed 
would  be  very  beneficial  to  health;  the  same  applies  to  the 


INDUSTRIAL  DUSTS  AND  HEALTH  91 

necessity  of  daily,  weekly,  and  seasonal  pauses,  in  form  of 
Sundays,  holidays,  and  vacations. 

Tension  of  Work. — The  effect  of  duration  of  work  will 
partly  depend  upon  the  tension  with  which  it  is  carried  on. 
When  work  is  performed  under  great  stress,  tension,  artificial 
stimulus,  etc.,  the  point  of  fatigue  arrives  sooner,  and  its  ill- 
effects  are  more  marked. 

Physical  Strain  of  Work. — The  carrying  of  too  heavy  loads, 
lifting  weights,  and  performing  too  great  physical  tasks  above 
the  strength  of  the  individual  are  bound  to  react  harmfully  and 
cause  cardiac  dilatation,  hernias,  dislocations,  aneurysms,  etc. 

Mental  Strain  of  Work. — Worry  and  responsibility  which  are 
such  regular  features  of  industry,  especially  among  the  owners, 
managers,  etc.,  are  followed  by  injuries  well  known  to  practi- 
tioners on  insanity  and  diseases  of  the  nervous  system. 

Compensation  and  wages  paid  to  workers  determine  their 
mode  and  standard  of  living,  their  hygienic  surroundings, 
and  their  social  and  economical  welfare,  and  are  important 
factors  of  health. 

INDUSTRIAL  DUSTS  AND  HEALTH. 

There  are  a  large  number  of  industries  accompanied  by  the 
production  of  a  considerable  amount  of  dust. 

The  effects  of  exposure  to  dust  upon  health  vary  according 
to  amount  of  dust  inhaled,  kind  and  character  of  dust,  the 
period  of  exposure,  the  individual  health  of  the  workers,  the 
condition  of  the  work,  and  many  other  factors. 

Certain  dust,  metal  or  mineral,  being  sharp-edged,  may 
cause  mechanical  injury  in  the  delicate  mucous  membranes 
of  the  respiratory  passages,  injuries  which  may  then  become 
foci  of  infection  in  the  presence  of  infective  germs. 

All  dusts  cause  an  irritation  of  the  mucous  membranes  of 
the  eyes,  nose,  mouth,  and  throat,  producing  catarrhal  condi- 
tions, and  causing  cough,  discharge,  and  expectoration. 

A  prolonged  inhalation  of  dust  produces  deposits  in  the 
bronchi  and  bronchioles  and  sometimes  in  the  parenchyma 
of  the  lung,  and  the  constant  irritation  produced  by  such 


92  INDUSTRIAL  HYGIENE 

deposits  may  cause  the  production  of  an  active  connective- 
tissue  inflammation  and  consolidation  of  lung  tissue  in  nodules 
and  distinct  areas. 

Various  kinds  of  dust  conditions  of  the  lungs  of  workers 
in  dusty  trades  are  recognized  according  to  the  kind  of  dust 
inhaled.  Although  they  all  bear  the  name  of  "pneumono- 
koniosis,"  they  are  subdivided  into  anthracosis  (coal  miner's 
phthisis),  siderosis,  chalicosis,  tabacosis,  etc. 

The  pathological  process  in  the  lung  may  be  purely  fibrinous, 
or  the  infection  may  become,  in  the  later  stages,  mixed  with 
tubercle  bacilli;  the  prevalence  of  mixed  infections  is  marked. 

The  constant  inhalation  by  workers  of  large  quantities 
of  dust  is  very  harmful  to  health,  and  is  the  cause  of  the 
increased  morbidity  from  respiratory  and  tuberculous  diseases 
and  of  increase  in  the  general  mortality  of  workers  in 
dusty  trades. 

According  to  Tatham,  the  mortality  from  tuberculosis  and 
respiratory  diseases  among  the  workers  of  twenty-two  dusty 
trades  was  twice  as  great  as  that  of  agricultural  workers,  and 
in  eight  industries  three  and  four  and  a  half  times  greater. 

According  to  Sommerfeld,  the  mortality  of  Berlin  workers 
in  dusty  occupations  was  5.42  per  1000,  while  at  the  same 
time  the  mortality  of  workers  in  non-dusty  trades  was  but  2.39. 

According  to  Frederick  Hoffman,  the  proportion  of  mortality 
from  consumption  in  22,987  deaths  from  all  causes  was  28 
per  cent,  of  the  mortality  from  all  causes  in  persons  over 
fifteen  years  of  age.  Contrasting  this  death  rate  among 
dusty  industry  workers  and  the  death  rate  from  consump- 
tion of  9.5  among  agricultural  and  other  outdoor  workers, 
the  large  increase  of  death  from  consumption  among  dusty 
workers  is  clearly  demonstrated. 

Dust  affects  the  worker  not  only  through  the  respiratory 
system,  but  also  through  the  digestive  tract;  it  also  causes 
injuries  to  the  eyes,  and  is  followed  by  certain  skin  affections. 

Hoffman's^  classification  of  dusty  trades  according  to  dust 
produced  is  as  follows: 

1  Mortality  from  Consumption  in  Dusty  Trades.  F.  Hoffman,  Bulletin 
of  the  Bureau  of  Labor,  vol.  Ixxix. 


INDUSTRIAL  POISONS  AND  HEALTH  93 

Group  I. — ^Exposure  to  Metallic  Dust:  Grinders,  polishers, 
tool  and  instrument  makers,  jewellers,  gold  leaf,  brass  workers, 
printers,  compositors,  engravers,  pressmen. 

Group  II. — Exposure  to  Mineral  Dust:  Stone,  marble, 
cement  workers,  glass  blowers,  glass  cutters,  diamond  cutters, 
potters,  plasterers,  paperhangers,  moulders,  core  makers, 
lithographers. 

Group  III. — ^Exposure  to  Vegetable-fibre  Dust:  Cotton 
ginning,  textile,  flax,  linen,  hemp,  cordage,  paper  manufac- 
turers, weavers,  spinners,  hosiery  knitting,  lace  making,  jute, 
and  woodwork. 

Group  IV. — Exposure  to  Animal  and  Mixed  Dust:  Furriers, 
taxidermists,  hatters,  silk,  wool,  and  worsted  workers,  carpet, 
rug,  rag,  and  shoddy  workers,  hair  matresses,  upholsterers, 
etc. 

According  to  Hofi^man,  the  mortality  rate  from  consumption 
varies  according  to  each  group. 

Thus  the  mortality  rate  of  metallic  trades  is  37.4  per  cent. ; 
organic  dust  is  23.7  per  cent.;  mineral  dust  is  28.6  per  cent.; 
vegetable  dust  is  27.4  per  cent.;  animal  and  mixed  is  32.2 
per  cent.;  all  dusty  trades  is  28  per  cent. 


INDUSTRIAL  POISONS  AND  HEALTH. 

The  chief  industrial  poisons  are  lead,  arsenic,  and  mercury, 
although  phosphorus,  copper,  zinc,  brass,  and  chromium 
poisoning  are  frequently  met  with  in  various  industries. 

Lead. — The  number  of  trades  in  which  lead  is  used  is  too 
large  to  be  all  named.  A  few  of  the  most  common  indus- 
tries in  which  lead  is  largely  employed  are  the  following: 
Lead  workers  and  smelters,  lead  miners,  printers,  filers, 
grinders, compositors,  typefounders,  typesetters,  lithographers, 
stereotypers,  potters,  enamel  makers,  glass,  gold,  silver,  and 
patent-leather  workers,  painters,  manufacturers  of  lead  shot, 
amber  workers,  plumbers,  etc. 

Lead  enters  the  system  by  the  lungs,  digestive  tract,  and 
through  the  skin. 


94  INDUSTRIAL  HYGIENE 

Lead  causes  acute  or  chronic  intoxication. 

The  effects  of  chronic  lead  poisoning  are  first  noticed  by 
the  following  symptoms:  constipation,  cramps  and  "lead 
colic,"  anemia,  bluish  line  on  edge  of  gums,  anorexia,  pain 
in  joints.  A  further  persistent  exposure  to  lead  poison  is 
followed  by  lead  palsy,  arthralgia  saturnina,  loss  of  motor 
power  in  hands  and  feet,  wrist-drop,  progressive  muscular 
paralysis,  multiple  neuritis,  temporary  or  permanent  blind- 
ness, convulsions,  insanity,  and  death. 

The  mortality  of  lead  workers  is  very  great  in  proportion  to 
other  workers. 

Women  and  children  suffer  more  greatly  than  men.  In 
some  lead-smelting  mines  in  Prussia  there  were,  in  1905,  145 
cases  of  lead  poisoning  with  3726  days  lost  among  766 
workers. 

Among  those  working  in  the  lead  trades,  printers  are  well 
known  by  their  high  mortality  from  tuberculosis. 

Arsenic. — Arsenic  is  very  extensively  used  in  the  arts  and 
trades.  Among  others,  it  is  used  by  taxidermists,  by  felt 
finishers,  manufacturers  of  fuchsine,  by  glass  workers,  wall- 
paper makers,  manufacturers  of  artificial  flowers,  textile 
fabrics,  bronze  colors,  by  painters,  paris  green  manufacturers 
and  packers,  etc. 

Arsenic  affects  the  skin,  gastro-intestinal  tract,  respiratory 
and  nervous  systems.  Upon  the  skin  arsenic  causes  eczem- 
atous  eruptions,  vesicles  or  pustules.  In  the  respiratory 
passages  arsenic  causes  catarrhal  inflammations.  Colic, 
gastritis,  diarrhea  and  gastro-intestinal  disturbances  are  the 
result  of  its  action  upon  the  gastric  tract.  Of  the  nervous  dis- 
orders due  to  arsenical  poison,  the  following  are  specially 
marked :  loss  of  tendon  reflexes,  progressive  muscular  atrophy, 
local  anesthesia,  multiple  neuritis,  trophic  sores,  ataxia,  etc. 

The  poison  enters  the  body  by  the  mouth,  lungs,  and  skin. 

Mercury. — The  industries  in  which  mercury  is  largely 
used  are,  among  others,  the  following:  quicksilver  mines,  also 
in  gold  and  silver  mines;  manufacture  of  barometers,  ther- 
mometers, electric  meters,  silvering  mirrors, '  manufacture 
of  pharamaceutical  preparations,  the  felt  and  fur  industries. 


INDUSTRIAL  POISONS  AND  HEALTH  95 

chemical  works,  powder  works,  artificial  flowers,  photography, 
lithography,  etc. 

The  mode  of  introduction  into  the  system  is  by  inhalation 
of  the  fumes,  by  ingestion  of  the  salts,  and  by  absorption 
through  the  skin. 

The  effects  of  chronic  mercurial  poisoning  manifest  them- 
selves by  stomatitis,  gastric  disturbances,  metallic  taste  in  the 
mouth,  inflammation  and  ulceration  of  the  gums,  cachexia, 
tremors,  paralysis,  melancholy,  loss  of  memory,  etc. 

The  percentage  of  mercurial  poisoning  among  mercurial 
workers,  ranges  according  to  some  authorities  from  25  to  85 
per  cent. 

Phosphorus. — ^The  danger  of  phosphorus  poisoning  is 
limited  almost  entirely  to  workers  in  match  factories,  where 
such  matches  are  made  from  the  yellow  phosphorus.  Red 
phosphorus  is  not  dangerous. 

Among  the  milder  symptoms  of  phosphorus  poisoning  are 
gastric  and  bronchial  catarrh,  anorexia,  caries  of  the  teeth. 
Necrosis  of  the  bones,  especially  of  the  lower  maxillary,  is  a 
frequent  sequel  of  phosphorus  poisoning  in  operatives  with 
caries  of  teeth. 

Brass. — Brass  is  an  alloy  of  zinc  and  copper,  and  brass 
founders,  cutters,  filers,  and  polishers  are  subject  to  effects  of 
the  brass  dust. 

Brass  workers  suffer  frequently  from  what  is  called  "brass 
founder's  ague,"  a  feverish  condition  accompanied  by  chills, 
shivering,  vomiting,  sweating,  headache,  and  depression. 

Copper  and  zinc  workers  are  sometimes  subject  to  the  effects 
of  inhalation  of  the  dusts  of  these  metals,  the  nature  of  which 
is  not  specially  characteristic. 

Bronze  workers  sufi^er  from  a  combination  of  poisons,  as 
the  bronze  powders  are  mixed  with  different  metallic  ingredi- 
ents each  having  its  specific  action. 

Chromium  is  used  in  the  manufacture  of  dyes,  coloring  of 
paper,  fabrics,  etc. 

The  effects  of  chromium  are  marked  on  the  skin,  nasal 
mucous  membrane,  in  which  they  cause  ulceration  and  per- 
foration, also  upon  the  eyes. 


96  INDUSTRIAL  HYGIENE 


INDUSTRIAL  GASES,  FUMES,  AND  VAPORS  AND  HEALTH. 

Occurrence  and  Frequency. — The  occupations  in  which 
perceptible  quantities  of  dust  or  definite  poisons  are  pro- 
duced are  few  in  comparison  with  the  vast  number  of 
industries  in  the  processes  of  which  some  noxious  gases, 
fumes,  or  vapors  are  evolved. 

The  industrial  •  processes  in  which  chemical  agents  and 
gases  are  produced,  which,  when  absorbed  or  inhaled,  may 
become  dangerous  to  life  and  health,  are  so  manifold  and 
diverse  that  but  a  mere  enumeration  would  take  several  pages. 
Nor  is  it  always  possible  to  trace  the  harm  done  to  workers 
in  some  of  the  chemical  trades  to  one  or  the  other  poison, 
or  gas,  or  fumes,  for  in  most  of  those  industries  complicated 
processes  are  carried  on  simultaneously,  evolving  a  number 
of  noxious  and  toxic  elements,  exposing  the  workers  to  a 
number  of  various  influences. 

Examples  of  Gas-producing  Industries. — The  coal-tar 
industry,  may  serve  as  an  illustration.  In  this  trade  there 
are  several  dozens  of  products  and  by-products  produced,  each 
of  which  may  be  injurious  to  health;  and  it  would  be  difficult 
to  determine  which  of  the  deleterious  influences  are  the  ones 
producing  the  most  injury.  In  the  india-rubber  trade,  as 
another  example,  the  workers  are  exposed  to  the  vapors  of 
naphtha,  to  the  fumes  of  carbon  disulphide,  to  excessive 
heat,  and  to  a  number  of  other  injurious  influences. 

Some  of  the  principal  gases  and  fumes  which  are  injurious 
I  to  health  are  the  following:  sulphur  dioxide,  sulphur,  hydro- 
j  gen,  and  other  sulphur  compounds ;  carbon  monoxide,  dioxide, 
bisulphide,  and  other  carbon  compounds;  nitric  acid,  hydro- 
chloric acid,  ammonia,  chlorine  gas,  iodine,  bromine,  petro- 
leum,  benzin,    nitrobenzol,   aniline   dyes,  and    all    coal-tar 
products,  chromium,  potassium,  alum,  iron,  lead,  turpentine, 
cyanogen  compounds,  dynamite,  etc. 
f/     The  dangers  from  gases  and  fumes  depend  on  the  toxicity 
of  the  substances,  the  irritating  nature  of  the  fumes,  the  corro- 
sive action  upon  skin  and  mucous  membranes,  the  danger 


INDUSTRIAL  INFECTIONS  AND  HEALTH  97 

from  burns,  scalds,  and  explosions,  and,  lastly,  from  the 
excessive  temperatures  which  are  the  rule  in  such  establish- 
ments. 

The  mode  of  introduction  into  the  system  is  different  from 
that  of  dusts,  or  of  poisons.  While  dust  acts  mostly  upon  the 
rjespiratDj:yL_syjtem,  gases  andfumes  have  specific  actions 
upon  the  eyes,  niucQU,s  membranes,  and  the  blood.  Some 
of  the  fumes  which  are  products  of  various  industries  act  as 
virulent  poisons,  and  their  action  may  prove  fatal  within  a 
shortjimejiiter  exposure,  as,  for  instance,  after  inhaling  gases 
like  carbon  monoxide,  sulphuretted  hydrogen,  bromine, 
chlorine,  cyanogen,  etc.  The  effects  of  irritating  gases  and 
fumes  upon  the  eyes,  the  skin,  and  mucous  membranes  has 
already  been  alluded  to,  and  are  very  marked  in  the  numerous 
skin  affections,  erosion  of  the  mucous  membranes  of  the  nose 
and  mouth,  and  the  various  ulcerative  and  inflammatory 
changes  in  the  skin  of  hands,  fingers,  face,  and  arms. 
"The  mortality  and  diseases  of  the  chemical  trades  is  very 
large.  According  to  Roth,  the  mortality  is  7  per  1000 
among  Austrian  workers.  The  diseases  by  which  they  are 
affected  were  distributed  as  follows:  25.7  per  cent,  were  burns, 
contusions,  and  scalds;  19.9  per  cent.,  affections  of  the  respira- 
tory tract;  14.7,  digestive  tract;  10.8  per  cent.,  skin  diseases; 
and  10.5  per  cent.,  general  diseases.  The  percentage  of 
mortality  from  respiratory  diseases  is  also  very  high. 

Among  the  chemical  trades  which  are  extremely  dangerous 
to  health  we  may  include  the  manufacture  of  bleaching 
powders. 

Chemical  trade  accidents  are  very  frequent;  indeed,  the 
number  of  industrial  accidents  is  greater  in  chemical  trades, 
th^  in  any  other  industry  except  the  extrahazardous. 


INDUSTRIAL  INFECTIONS  AND  HEALTH. 

Dangers  from  Infection. — ^There  are  a  number  of  trades  in 
which  the  workers  are  exposed  to  infection  by  pathogenic 
germs  which  may  adhere  to  the  material  of  the  work. 
7 


98  INDUSTRIAL  HYGIENE 

Trade  Infections .  —  Tailors,  rag  pickers,  rag  sorters, 
laundry  workers,  etc.,  may  be  infected  by  germs  of  scarlet 
fever,  typhoid,  diphtheria,  etc.,  which  may  adhere  to  the 
stuffs  upon  which  they  work;  gardeners  may  be  infected 
with  tetanus;  horsemen,  coachmen,  etc.,  with  glanders;  wool- 
sorters,  tanners,  skinners,  with  anthrax;  nurses  with  various 
communicable  diseases  of  the  persons  of  whom  they  take 
care;  tunnel  workers  with  anchylostomiasis. 

"Rag  sorter's  disease"  is  a  name  given  to  infection  with 
anthrax  from  which  handlers  of  wool,  hides,  and  hairs  of 
animals  dying  of  anthrax  may  suffer  at  times.  According 
to  Neisser,  there  were  269  cases  of  anthrax,  with  67  deaths, 
in  England  between  the  years  1899  and  1904.  Kober  quotes 
Ravenal  as  reporting  twelve  cases  of  anthrax  in  three  localities 
in  Pennsylvania  during.  1897. 

"Anchylostomiasis"  is  an  infective  disease  from  which 
many  tunnel  workers  suffer.  In  one  pit  in  Hungary  80  per 
cent,  of  all  the  workers  suffered,  in  another  in  the  province  of 
Liege,  50  to  60  per  cent,  had  the  disease.  The  malady  which 
presents  an  aggravated  form  of  pernicious  anemia  is  due  to  a 
minute  parasite,  or  hookworm,  which  fixes  itself  by  its  booklets 
in  the  upper  part  of  the  small  intestine  and  sucks  the  blood. 
The  infective  parasite  is  found  in  the  excreta,  by  means  of 
which  the  infection  spreads. 

Tuberculosis. — The  dangers  of  infection  with  the  tubercle 
bacilli  is  not  peculiar  to  industries,  although  nowhere  as  much 
as  in  industries  are  all  the  conditions  present  for  the  infection 
and  its  spread  as  among  such  a  large  number  of  persons. 
Tuberculosis  is  so  prevalent  among  workers,  especially  in 
dusty  trades,  that  it  may  be  called  a  disease  of  workingmen. 


INDUSTRIAL  ACCIDENTS  AND  HEALTH. 

Occurrence. — While  accidental  injury  to  the  worker  may  take 
place  in  every  industry  and  trade,  there  are  some  trades 
which  involve  peculiarly  extrahazardous  work  because  of  some 
of  the  conditions  under  which  they  are  carried  on.     Thus, 


INDUSTRIAL  ACCIDENTS  AND  HEALTH  99 

workmen  on  high  buildings,  bridge  workers,  miners,  and 
tunnel  workers,  manufacturers  of  explosives,  workers  in 
blast  furnaces,  iron,  steel,  and  other  metal  makers,  rail- 
road men,  chemical  workers,  and  many  other  workers  in 
many  other  industries  are  exposed  to  special  dangers  from 
accidents. 

Besides  the  trades  enumerated  there  are  special  elements 
of  danger  in  all  factories  and  establishments  where  any  kind 
of  machinery  is  used,  the  hazards  due  to  the  various  wheels, 
belts,  gears,  saws,  fly-wheels,  knives,  sharp  edges,  etc.,  of  the 
machinery. 

Varieties  of  Injury. — The  accidental  injuries  vary  in  their 
extent  and  importance  from  slight  burns,  scalds,  dislocations, 
bruises,  wounds,  injuries,  fractures  to  loss  of  eye,  limb,  fracture 
of  scull,  and  sudden  death.  The  injuries  may  be  slight,  or 
they  may  lead  to  grave  results,  or  may  be  fatal  at  once. 

The  amount  of  suffering,  loss  of  work,  and  distress  to 
families  of  workers  is  appalling. 

Among  the  railroad  employees  there  were  in  the  United 
States  not  less  than  53,046  killed  while  at  work  from  the 
years  1888  to  1907,  and  more  than  800,000  employees  were 
either  maimed  or  crippled. 

The  number  of  accidents  in  the  various  industries  is  enor- 
mous. According  to  Hoffman,  there  are  nearly  2,000,000 
accidents  every  year  in  the  United  States,  of  which  30,000 
are  directly  fatal,  while  many  of  the  others  are  followed 
by  partial  or  total  permanent  disability  of  the  injured 
workers. 

Upon  an  analysis  of  the  causes  of  the  various  accidents 
in  industry,  one  may  find  that  most  of  them  may  be  due  to 
one  of  the  following  causes:  faulty  construction  of  place  of 
work  or  of  implements;  unguarded  machinery;  unremedied 
defects  in  construction,  machinery,  etc.;  dangerous  materials, 
explosives,  etc.;  inadequate  and  incompetent  supervision; 
insufficient  warning  signals,  etc.;  too  long  hours  of  work,  too 
great  tension;  overwork,  fatigue,  and  overstrain;  ignorance, 
youth,  and  inexperience  of  workers;  criminal  negligence  of 
foremen,  etc.;  recklessness,  carelessness,  etc.,  of  employees. 


100  INDUSTRIAL  HYGIENE 

Almost  all  industrial  accidents  may  be  traced  to  one  or 
more  of  the  above  causes  enumerated,  most  of  which  are 
preventable  and  avoidable. 


INDUSTRIAL  PROPHYLAXIS. 

Two  Classes  of  Industrial  Disease . — In  the  study  of  the  ill- 
effects  of  industries  on  health,  of  the  various  adverse  condi- 
tions incident  to  different  trades,  and  of  the  manifold  causes 
of  industrial  diseases,  we  find  many  of  them  necessary  and 
unavoidable;  but  there  are  also  many,  if  not  most,  which  are 
not  necessary,  may  be  avoided,  and  are  entirely  preventable. 

Some  of  the  causes  of  industrial  diseases  lie  not  only  in  the 
unavoidable  industrial  processes  and  materials,  but  also  in  the 
ignorance  and  carelessness  of  the  employees  themselves,  and 
more  so  in  the  greed,  covetousness,  false  economy,  and  cruelty 
of  the  employers,  who  neglect  the  simplest  health  precautions 
and  leave  machinery  and  other  devises  unprotected  because 
of  the  small  cost,  which  is  infinitesimal  in  comparison  with  the 
cost  to  the  public  health  of  the  injuries  and  accidents  due  to 
them. 

The  aim  and  purpose  of  industrial  hygiene  is  to  abolish  all 
preventable  adverse  industrial  conditions,  the  ideal  of  hygiene 
being  that  industrial  life  should  be  a  blessing  to  health  and 
conducive  to  it,  instead  of  harmful  and  injurious. 

The  demands  of  industrial  hygiene,  therefore,  meet  a  twofold 
resistance  on  the  part  of  the  two  classes  in  whose  interest 
it  should  work,  a  resistance  that  may  be  overcome  but  in  two 
ways :  on  the  one  hand,  in  the  general  education  of  the  work- 
ing people  and  the  general  public  in  the  ill-effects  of  many 
industries  and  in  the  preventable  nature  of  most  of  them; 
and,  on  the  other  hand,  in  compulsory  legislation  protecting 
the  workingman  against  himself  and  especially  against  the 
effects  of  injuries  caused  by  preventable  elements,  said 
legislation  compelling  the  employers  to  put  their  plants  and 
processes  on  a  sanitary  basis,  with  a  view  to  save  life  and 
health. 


SANITATION  OF  THE  WORKPLACE  101 

The  brief  review  of  the  prophylactic  measures  enumerated 
below  includes  measures  which  either  are  already  em- 
braced in  the  codes  of  industrial  legislation  in  this  or  other 
countries,  or  such  as  are  seriously  discussed  and  are  bound  to 
become  laws  sooner  or  later  in  the  progress  of  industrial 
hygiene. 

SANITATION  OF  THE  WORKPLACE. 

The  construction  of  industrial  establishments  should  be 
definitely  designed  for  the  specific  purposes  to  be  carried  on 
therein,  and  the  common  practice  of  having  any  ramshackle 
building  fitted  up  for  factory  purposes  should  be  pro- 
hibited. 

The  size  of  the  workplace  should  correspond  to  the  number 
of  employees  and  to  the  peculiar  needs  of  the  establishment. 
The  minimum  of  400  cubic  feet  of  space  for  every  workman 
which  is  established  by  legislation  in  many  places  is  in- 
adequate in  most  industries  unless  there  is  a  system  of 
mechanical  ventilation,  otherwise  the  cubic  feet  space  should 
be  raised  to  at  least  1000  cubic  feet,  and  more,  especially  in 
dusty  trades. 

The  walls,  floors,  ceilings,  and  all  other  surfaces  in  factories 
should  be  smooth,  without  crevices,  nooks,  corners,  mouldings, 
etc.,  and  should  be  finished  with  some  non-absorbent,  light- 
colored  materials,  easily  washed  off  and  cleansible.  When- 
ever practicable,  the  floors  are  best  made  of  concrete,  tiles, 
or  glass;  this  is  especially  necessary  where  mercury,  lead,  or 
other  poisons  are  worked  with  and  are  liable  to  accumulate 
in  crevices  and  rough  surfaces  of  floors. 

There  should  be  ample  provision  for  water-supply  fixtures, 
for  drinking  purposes  as  well  as  for  washing,  which  is  an 
important  prophylactic  measure  in  dusty  and  poisonous  trades. 
The  washrooms,  bathrooms,  and  toilet  accommodations  are 
usually  provided  separately  for  the  male  and  female  workers, 
and  are  put  into  apartments  with  tiled  floors  and  walls. 

Upon  the  proper  lighting  facilities  depend  not  only  the  con- 
dition of  the  eyesight  of  the  workers,  but  also  their  general 


102  '  INDUSTRIAL  HYGIENE 

health.  The  ideal  workplace  is  the  one  where  any  other 
illumination  but  that  of  sunlight  is  avoided;  if  artificial 
illumination  is  unavoidable,  it  should  be  electric  light,  as  it 
produces  the  best  light  with  the  least  impurities.  Whenever 
artificial  illumination  is  used  it  should  be  placed  at  proper 
distances  from  the  workers,  there  should  be  a  uniform 
distribution,  and  the  light  should  not  be  too  glaring  and 
produce  as  little  heat  and  impurities  as  possible. 

Ventilation  is  the  corner-stone  of  industrial  hygiene;  for 
by  far  the  greatest  part  of  the  dangers  which  threaten 
workers  are  due  to  the  impurities  in  the  air  of  the  workplaces. 
While  natural  ventilation  may  be  sufficient  for  dwelling  houses 
with  the  comparatively  few  persons  in  every  room,  it  is  insuffi- 
cient and  entirely  inadequate  in  industrial  establishments, 
even  with  all  the  artificial  devices,  openings  for  inlets  and 
outlets  that  may  be  installed.  Nothing  short  of  mechanical 
ventilation  should  be  allowed  in  any  factory  where  a  number 
of  people  work  at  any  trade,  especially  one  producing  more 
or  less  dust.  With  the  introduction  of  mechanical  power, 
steam,  water,  and  electricity,  in  almost  all  industrial  estab- 
lishments, there  is  no  reason  why  every  factory  should  not 
be  provided  with  an  efficient  system  of  mechanical  vacuum 
and  plenum  system  of  ventilation,  to  remove  all  dust  and 
impurities  in  the  air  and  bring  in  pure  air  from  the  outside. 
A  good  system  of  ventilation  in  factories  would  not  only 
prevent  the  inhalation  of  air  impurities,  but  would  also  pro- 
mote the  health  of  the  workers  and  make  them  industrially 
more  efficient. 

Dust. — The  prophylaxis  of  the  injurious  effects  of  dust 
may  be  summarized  in  the  following  measures: 

1.  Separation  of  the  dusty  processes,  or  trades,  or  part 
of  trades  from  any  other  less  dust-producing  trades,  and 
their  concentration  in  special  establishments,  or  in  specially 
constructed  rooms. 

2.  Substitution  of  machinery  for  handwork  in  all  dusty 
processes,  with  the  resulting  decrease  in  the  number  of 
workers  subject  to  dust,  and  with  the  possibility  of  better 
control  of  the  dusty  process. 


SANITATION  OF  THE  WORKPLACE  103 

3.  Substitution  of  the  wet  method  for  the  dry  production ;  that 
is,  all  materials  and  processes  producing  dust  should  be  well 
moistened  during  the  process.  This  may  easily  be  done  in 
the  filing,  cutting,  grinding,  polishing,  and  similar  dust- 
producing  industries,  with  a  consequent  large  elimination  of 
dust. 

4.  Isolation  of  the  Worker  from  the  Dust. — ^This  may  be 
accomplished  in  several  ways :  (a)  By  separating  the  worker 
from  the  dust-producing  machine,  etc.,  by  a  glass  or  other  wall 
or  screen;  (b)  by  protecting  the  nose  and  mouth  of  the  worker 
by  specially  constructed  "respirators,"  which  are  made  prop- 
erly adjusted  to  the  face  with  a  filtering  medium  catching 
the  dust;  (c)  by  enclosing  the  most  dusty  processes  in  tight 
rooms,  the  machinery,  etc.,  of  which  is  worked  from  the 
outside  by  electricity  or  tools  handled  from  the  outside. 

5.  Instant  and  continuous  removal  of  the  dust  produced  by 
special  vacuum  hoods  and  tubes  covering  every  dust  producing 
machine  process,  all  dust  being  exhausted  by  a  motor  power 
operated  from  one  central  location,  which  by  means  of  a 
series  of  ducts  and  tubes  is  connected  with  every  worker's 
bench  or  machine. 

One  or  more  of  these  prophylactic  measures  must  be  em- 
ployed in  every  dusty  occupation,  with  resulting  saving  of  life 
by  preventing  the  ill-efi'ects  of  dust  upon  health. 

The  prophylaxis  of  industrial  poisons,  gases,  and  fumes 
does  not  difi^er  in  its  essential  features  from  the  prophylactic 
principles  laid  down  for  dusty  occupations,  except  that  they 
must  be  more  strictly  and  carefully  enforced.  When  dealing 
with  poisons  and  gases,  it  is  still  more  important  to  avoid 
all  preventable  conditions,  in  the  use  of  the  ingredients  as 
well  as  in  the  various  processes  of  production.  There  are 
certain  poisonous  materials  which  may  be  entirely  eliminated 
from  trades  without  any  detriment  to  the  trades;  this  is 
notably  the  case  with  the  use  of  yellow  phosphorus  in  match 
manufacture,  in  which  it  has  been  practically  demonstrated 
that  the  substitution  of  the  red  phosphorus  does  not  hurt 
the  industry,  produces  a  match  of  good  quality,  and  absolutely 
does  away  with  the  dangers  of  phosphorous  poisoning.     The 


104  INDUSTRIAL  HYGIENE 

same  may  apply  to  use  of  lead  in  pottery  glaze,  in  which  it 
has  also  been  demonstrated  that  the  use  of  leadless  glazes 
is  cheap,  efficient,  and  without  danger  to  health.  This  may 
also  be  applied  to  the  use  of  lead  in  paints,  in  toys,  the  use 
of  mercury  in  silvering  mirrors,  and  the  substitution  of  non- 
toxic elements  and  processes  in  many  other  industries, 
NothintT  short  of  eliminating  all  toxic  elements  from  all  indus- 
tries will  satisfy  hygiene,  but  industrial  legislation  should 
insist  in  prohibiting  the  use  of  any  toxic  substance  which 
may  be  readily  substituted  by  a  non-poisonous  one. 

The  removal  of  gases  and  fumes  produced  by  appropriate 
machinery  and  ventilation  is  even  more  important  than  in 
the  case  of  dust. 

The  prophylaxis  of  industrial  infection  from  hair,  hides, 
cloths,  etc.,  consists  in  a  thorough  disinfection  of  all  suspi- 
cious materials  and  proper  precautions  of  the  employees  in 
handling  such  products  and  materials. 

Industrial,  Personal,  and  Other  Prophylaxis. — The  following 
are  some  of  the  essential  measures  necessary  for  the  preven- 
tion of  the  ill-efiects  of  industry  upon  health. 

1.  Proper  supervision  and  control  of  selection  of  trade. 

2.  Manual  training  and  education. 

3.  Personal  cleanliness,  etc. 

4.  Restriction  of  female  labor. 

5.  Abolition  of  child  labor. 

6.  Prohibition  of  home  work, 

7.  Regulation   of  excessive  temperature,  humidity,  etc. 

8.  Prevention  of  fatigue,  overwork,  etc. 

9.  Security  of  wages,  rate  of  compensation,  etc. 

10.  Prevention  of  accidental  injuries,  etc. 

11.  Medical  factory  inspection. 

12.  Public  control  of  environmental  conditions. 

13.  State  insurance,  etc. 

1.  The  selection  of  a  trade,  which  at  present  is  so  hap- 
hazard and  without  previous  thought,  should  be  better  regu- 
lated, as  upon  it  depends  the  subsequent  influence  of  the  in- 
dustry upon  the  health.  Persons  of  tuberculous  tendencies 
should  avoid  dusty  occupations,  robust  persons  should  select 


SANITATION  OF  THE  WORKPLACE  105 

strenuous  occupations,  while  less  robust  should  be  assigned 
to  inactive  and  less  arduous  work.  There  is  no  reason  why 
factories  and  all  industrial  establishments  should  not  subject 
the  applicant  to  a  rigid  preliminary  physical  examination,  the 
same  as  the  State  subjects  the  voluntary  military  recruit.  This 
is  already  done  in  many  civil  service  positions  in  State  and 
municipal  departments;  also  in  many  railroad  and  other  transit 
systems,  and  if  made  a  permanent  policy  in  all  trades,  would 
assure  a  better  and  more  efficient  class  of  workers,  as  well  as 
protect  these  against  the  effects  of  trade  diseases. 

2.  The  preliminary  manual  training  of  apprentices  and 
applicants  of  trades  in  the  science  and  art  of  their  professions 
would  be  a  great  preventive  against  the  ill  effects  of  many 
industries  by  educating  a  class  of  workers  well  acquainted 
with  their  trades,  with  the  processes  and  with  the  machinery 
used,  as  well  as  with  the  ordinary  precautions  to  be  used 
against  any  and  all  untoward  influences  in  the  trades. 

3.  The  supervision  of  the  personal  cleanliness  and  personal 
hygiene  of  the  workers  should  be  part  of  the  education 
of  the  workers  themselves,  should  also  be  part  of  the  duty 
of  their  employer,  as  well  as  a  duty  of  the  State  factory 
inspectors. 

The  wearing  of  proper  clothing,  the  compulsory  washing 
of  hands,  and  use  of  washrooms  in  all,  especially  in  dusty 
and  poisonous,  occupations,  the  wearing  of  respirators  when 
needed,  the  avoidance  of  alcoholic  stimulation  and  other 
offensive  habits,  etc.,  are  all  matters  of  great  importance  to 
health;  and  until  the  workers  are  themselves  educated  to  use 
these  measures  without  compulsion,  should  be  under  the 
control  of  State  authorities. 

4.  There  is  abundant  legislation  for  the  restriction  of 
female  labor,  especially  restriction  of  age,  of  work  periods,  of 
night  work,  of  work  during  pregnancy,  during  convalescence 
after  labor,  etc.  Such  legislation  is  as  yet  very  ununiform 
in  various  States  and  various  places,  very  laxly  observed  in 
many  industries,  and  should  be  more  scientifically  elabo- 
rated, made  more  uniform  throughout  the  country,  and  rigidly 
enforced  by  factory  inspection. 


106  INDUSTRIAL  HYGIENE 

5.  There  are  no  reasons  for  child  work;  neither  economic 
nor  social,  nor  sanitary,  and  the  consensus  of  opinion  is 
that  child  labor  is  a  curse  and  should  be  abolished  in  all 
civilized  communities.  No  compromises  should  be  made, 
and  the  age  of  beginning  of  any  work,  except  educational, 
should  be  limited  to  at  least  sixteen  years  for  males  and 
eighteen  for  females. 

6.  Home  work  is  prohibited  at  present  by  many  States 
with  regard  to  many  industries,  although  it  is  still  allowed, 
though  to  be  licensed,  in  the  clothing  industry.  A  further 
restriction,  or  total  prohibition,  of  home  work  would  certainly 
be  beneficial  to  health. 

7.  The  control  of  adverse  conditions  in  industries,  as  alluded 
to  in  a  previous  section,  such  as  extremes  in  temperature, 
in  light,  humidity,  etc.,  air  pressure,  are  better  studied  each 
separately,  and  the  prophylaxis  is  possible  in  many  cases,  and 
the  ill-effects  preventable  in  most  cases  by  proper  care,  atten- 
tion and  installations  of  labor-saving  and  safety  devices,  the 
discussions  of  which  cannot  be  gone  into  here. 

8.  The  prevention  of  the  ill-effects  of  fatigue  consist  in 
adjusting  of  the  work  to  the  capacity  of  each  individual,  in 
avoidance  of  too  arduous  tasks,  of  overestimating  strength. 
in  introduction  of  machinery  in  difficult  labor,  in  shortening 
the  hours  of  labor,  in  lengthening  the  pauses  between  labor 
periods,  in  the  cessation  of  work  during  parts  of  day,  parts 
of  week,  season  and  year,  and  in  the  avoidance  of  strain, 
tension,  overwork,  etc. 

9.  The  security  of  work  and  place,  the  regulation  of  the  rate 
of  wages  to  the  standard  of  living,  and  other  conditions 
are  matters  of  social-economic  consideration  rather  than  of 
hygiene,  although  they  play  such  an  important  role  in  the 
effects  of  trades  upon  health. 

10.  The  prevention  of  accidents  by  machinery  or  other 
causes  is  a  science  by  itself.  Most  countries  have  enacted 
rigid  laws  for  the  protection  of  employees  from  machinery 
and  to  prevent  accidents  generally.  Motors,  engines,  and  fly- 
wheels may  be  fenced  in  and  provided  with  proper  guards 
and  rails.     Wheels,  shafts,  drums,  belts,  gearing,  etc.,  may 


SANITATION  OF  THE  WORKPLACE  107 

be  encased  and  protected  by  special  devices.  Special  rules 
in  each  industry  are  necessary  to  prevent  the  elements  of 
risk  peculiar  to  each  trade. 

■  11.  Factory  inspection  is  already  a  recognized  state  insti- 
tution, and  has  done  much  toward  the  amelioration  of  the 
conditions  of  labor.  In  order  to  increase  the  benefits  of  this 
institution  part  of  the  control  of  industries  should  be  in  the 
hands  of  qualified  physicians.  Medical  factory  inspe  tion  is 
a  demand  of  modern  industrial  hygiene  no  less  than  medical 
school  inspection.  A  comprehensive  medical  factory  in- 
spection embraces  the  following  features:  state  licensing 
of  trades  and  industrial  establishments;  preliminary  physical 
examination  of  applicants  for  employment;  periodical  medical 
inspection  and  examination  of  workers;  exclusion  of  all 
physically  unfit,  or  suffering  from  incipient  disease;  sanitary 
inspection  of  places  of  trades  and  all  sanitation.  Medical 
factory  inspection  is  already  a  fact  in  many  European  coun- 
tries where  its  great  benefit  to  public  health  has  been  already 
■  recognized. 

12.  The  public  control  of  environmental  conditions,  the 
improvements  in  the  housing  of  the  working  classes,  the 
spread  of  education,  the  better  systems  of  popular  nutrition, 
and  similar  sanitary  improvements  are  already  parts  of  the 
duties  of  social  workers  and  public  health  progress. 

13.  Finally,  the  promotion  of  public  health  demands  the 
institution  of  new  measures  for  the  protection  of  the  workers, 
as  well  as  the  general  community,  by  means  of  compulsory 
health  insurance.  Insurance  against  accidents,  against  sick- 
ness, against  death,  against  unemployment,  and  similar 
insurance  is  already  introduced  in  many  countries,  and  the 
principle  of  it  is  rapidly  spreading  and  promises  to  become 
a  definite  corner-stone  of  industrial  legislation  and  welfare. 

The  effects  of  a  comprehensive  state  insurance  of  industrial 
workers  on  public  health  would  certainly  be  very  great,  and 
would  be  the  best  achievement  of  public  hygiene. 


108  INDUSTRIAL  HYGIENE 


QUESTIONS, 

Define  industrial  hygiene. 

Sum  up  the  effects  of  occupation  upon  health. 

Name  the  principal  groups  of  factors  causing  industrial  disease, 

AVhat  are  the  effects  of  an  unwise  selection  of  trade? 

To  what  are  due  the  ill-effects  of  women  labor? 

To  what  are  due  the  ill-effects  of  child  labor? 

What  effect  has  the  place  of  work  upon  health? 

Name  the  various  adverse  industrial  conditions. 

What  effects  have  extremes  of  temperature  on  health  ? 

What  effects  have  adverse  conditions  of  humidity,  light,  and  position? 

What  effects  have  variations  of  air  pressure? 

What  is  caisson  disease,  and  what  are  its  symptoms  ? 

Wliat  are  the  ill-effects  of  fatigue? 

What  are  the  "fatigue  neuroses"? 

What  is  the  effect  upon  health  of  constant  dust  inhalation? 

Classify  various  trades  according  to  kind  of  dust  produced. 

Name  the  "industrial  poisons." 

What  is  the  effect  of  lead,  acute,  and  chronic  poisoning? 

What  are  the  symptoms  of  arsenical  industrial  poisoning? 

What  are  the  effects  of  mercury  industrial  poisoning? 

What  are  the  effects  of  phosphorus  poisoning? 

What  injurious  gases  and  fumes  are  found  in  industries? 

What  is  the  difference  in  the  effects  of  poisons  and  gases? 

In  what  trades  is  there  danger  of  bacterial  infection  ? 

What  are  the  common  causes  of  industrial  accidents? 

What  are  the  essential  elements  of  a  sanitary  workshop? 

What  are  essential  elements  in  the  prevention  of  effects  of  dust  ? 

What  are  the  prophylactic  measures  in  toxic  industries  ? 

What  are  measures  to  prevent  effects  of  gases  and  fumes  ? 

What  are  elements  of  personal  industrial  prophylaxis?    . 

What  are  the  measures  for  preventing  industrial  infection? 

What  are  the  measures  for  preventing  industrial  accidents? 

What  are  essential  elements  of  medical  factory  inspection? 

What  are  the  forms  of  industrial  State  and  private  insurance? 


CHAPTER  V. 

PUBLIC  WATER  SUPPLY. 

'  Water  Supply  and  Public  Health. — One  of  the  important 
branches  of  public  hygiene  is  a  consideration  of  the  public 
water  supply  and  its  relation  to  public  health,  the  dangers 
of  impure  water  and  the  diseases  due  to  them,  and  the 
means  and  methods  of  insuring  the  public  a  pure  and  abun- 
dant water  supply  for  all  purposes. 

The  consideration  of  the  construction  of  resen^oirs,  aque- 
ducts, filter  plants,  etc.,  is  within  the  domain  of  sanitary  art 
or  engineering. 

The  intimate  relation  of  water  to  health  has  been  recognized 
from  time  immemorial.  Important  as  are  all  the  various 
impurities  that  are  often  found  in  water,  the  greatest  impor- 
tance, so  far  as  health  is  concerned,  is  ascribed  to  the  organic 
ingredients,  and,  especially,  to  the  parasitic  ova  and  to  the 
pathogenic  germs  which  may,  at  times,  contaminate  the 
water. 

Of  the  parasitic  ova  in  water,  which,  on  ingestion  by  human 
beings,  may  develop  and  endanger  health,  the  following  are 
of  the  most  importance:  taenia  solium,  lata,  etc.;  oxyuris 
vermicularis,  ascaris  lumbricoides,  filaria  dracunculus,  filaria 
sanguinis  hominis,  anchylostomum  duodenale,  bilharzia  hem- 
atobia,  distomum  hsematobimum,  leeches,  etc. 

Pathogenic  microbes  in  water  may  embrace  all  known  kinds, 
although  they  differ  much  as  to  their  virulence,  when  in  this 
medium. 

The  specific  microorganisms  of  diphtheria,  tuberculosis, 
tetanus,  anthrax,  malignant  edema,  and  others  have  been 
demonstrated  at  different  times  in  water,  but  their  action 
and  influence  on  human  health  have  as  yet  not  been  exactly 
defined  or  demonstrated. 

( 109  ) 


no  PUBLIC  WATER  SUPPLY 

The  most  important  microorganisms  which  have  been 
found  in  water,  and  to  which  the  so-called  "water-borne  dis- 
eases" are  due,  are  the  pathogenic  germs  of  cholera,  typhoid, 
dysentery,  "Weil's"  disease,  and  some  gastro-intestinal  affec- 
tions. 

The  connection  of  dysentery,  malaria,  goitre  and  cretin- 
ism, yellow  fever,  and  other  diseases  with  drinking  water 
has  been  urged  and  claimed  by  a  number  of  investigators, 
although  it  has  not  as  yet  been  possible  to  successfully  dem- 
onstrate their  exact  relations. 

The  causation  of  gastro-intestinal  disease  by  drinking 
water  has  been  fully  proved,  although  the  exact  germ  to 
which  it  may  be  due  has  as  yet  not  been  fully  agreed  upon. 

The  connection  between  water  and  malignant  edema, 
tetanus,  anthrax,  have  been  fully  demonstrated  and  proved 
to  be  due  to  the  ingredients  of  animal  excreta  contaminating 
water. 

The  greatest  achievements  of  sanitary  science  have  been 
the  complete  and  practical  demonstration  of  the  causative 
relations  between  impure  drinking  water  and  cholera  and 
typhoid  fever. 

Water  Supply  and  Cholera. — In  his  classic  essay,  "On  the 
Mode  of  Communication  of  Cholera,"  published  in  1855, 
Dr.  Snow  was  the  first  to  show  the  relation  of  cholera  to 
drinking  water,  long  before  the  specific  microbe  of  cholera 
had  been  discovered  by  Robert  Koch  (1884). 

In  the  frequent  marches  of  the  dread  Asiatic  cholera  from 
its  birthplace  in  the  East  through  the  highways  and  bj^ways 
of  Europe  it  was  noticed  that  certain  towns  and  places  were 
invariably  spared,  and  on  examination  it  has  always  been 
found  that  such  places  received  their  water  supply  from  sep- 
arate sources  not  connected  with  other  places. 

In  the  six  epidemics  through  which  the  city  of  Halle  went 
it  was  found  that  one  quarter  of  the  city  enjoying  a  separate 
water  supply  from  springs  invariably  escaped  the  epidemic. 

In  the  London  epidemic,  in  1849,  when  the  whole  city  was 
supplied  by  two  companies  with  water  from  the  Thames, 
the  whole  city  suffered  equally,  while  in  the  epidemic  of  1854, 


WATER  SUPPLY  AND  CHOLERA  111 

when  one  part  of  the  city  was  suppHed  by  one  company  from 
a  more  distant  part  of  the  river,  while  the  other  part  of  the 
city  was  supplied  from  the  old  source,  it  was  found  that  the 
part  of  the  city  supplied  from  the  new  source  suffered  three 
and  a  half  times  less  than  the  part  supplied  from  the  old 
source. 

But  the  clearest  and  most  valuable  proof  was  found  in  the 
London  epidemic  of  1854,  when  it  was  found  that  the  mor- 
tality in  one  particular  parish — that  of  St.  James — was  at 
the  rate  of  220  per  10,000,  while  in  the  immediately  adjoining 
parishes  it  was  but  at  the  rate  of  9  and  33  per  10,000.  In 
that  same  St.  James  parish,  in  the  epidemic  of  1849,  the 
mortality  was  but  15  per  10,000. 

Upon  a  most  painstaking  and  thorough  investigation  it  was 
discovered  that  the  infection  was  due  to  one  contaminated 
well  in  Broad  Street,  a  pump  into  which  drained  an  open 
cesspool,  or  privy,  from  an  adjoining  house,  which  privy 
was  clearly  contaminated  by  the  cholera  germs,  at  that  time 
not  yet  discovered.  In  Broad  Street,  not  distant  from  the 
place  where  the  cholera  cases  were  developing  daily,  there 
was  a  brewery,  with  seventy  workmen,  who  enjoyed  entire 
immunity,  but  they  were  supplied  with  drinking  water  from 
a  special  well  within  the  brewery. 

The  case  of  Hamburg  is  no  less  classical,  and  often  quoted. 
In  1892  there  was  in  Hamburg  an  epidemic  of  cholera  lasting 
four  months,  but  while  one  section  of  the  city  was  infected 
and  numerous  cases  were  cropping  out  daily,  the  adjoining 
part  of  Hamburg,  called  Altoona,  which  enjoyed  a  separate 
water  supply  from  the  same  river,  the  Elbe,  but  which  was 
filtered,  was  comparatively  free  from  the  ravages  of  the  epi- 
demic. 

In  1884  it  was  at  last  possible  for  Robert  Koch  to  demon- 
strate the  cholera  comma  bacillus  in  the  infected  wells  of  a 
cholera  district  in  Calcutta,  and  since  then  the  etiological 
relation  of  water  and  cholera  was  established  beyond  dispute. 

More  important,  because  of  the  greater  frequency  and  the 
endemic  character  of  typhoid  fever,  is  the  clear  proof  of  the 
relation  of  drinking  water  and  typhoid  fever. 


112  PUBLIC  WATER  SUPPLY 

The  epidemics  of  typhoid  in  Lauzanne,  Switzerland,  in 
1872;  in  Red  Hill,  England;  in  Plymouth,  Pa.,  in  1885;  in 
Lowell  and  Lawrence,  Mass.;  in  Ithaca,  N.  Y.;  in  Philadel- 
phia, are  commonly  quoted  as  examples  of  the  demonstrated 
effects  of  polluted  water  supplies  in  the  causation  of  typhoid 
fever. 

What  may  be  accomplished  by  a  purified  water  supply  was 
demonstrated  by  the  city  of  Lawrence,  Mass.,  which  reduced 
its  death  rate  from  tj^hoid  from  10  to  12  per  10,000,  before 
1893,  to  almost  0  after  installing  an  efficient  filtering  plant. 

Source  of  Infection  of  Water  Supply. — ^The  water-borne 
diseases  come  from  the  germs  found  in  drinking  water; 
but  whence  comes  the  germs?     What  is  their  source? 

Chemically  pure  water  is  rarely  found  except  in  the  chemist's 
flask.  Being  a  lyaiversal  solvent  and  diluent,  water  almost 
always  contains  some  organic  or  inorganic  matter  suspended 
or  diluted  in  it.  Even  rain  water,  which  is  pure  before  it 
comes  within  the  ground  atmosphere,  immediately  takes  up 
any  impurities  with  which  it  comes  into  contact  during  its 
fall  upon  the  ground. 

It  is  obvious  that  surface  water  as  well  as  subsoil  water 
are  still  more  contamThated  than  rain  water,  the  media 
through  which  they  go  imparting  to  the  water  a  large  part  of 
their  constituents.  Indeed,  there  are  hardly  any  sources  of 
water  which  may  not  be  causes  of  water  contamination  with 
various  impurities. 

The  most  important  matter  which  often  contaminates  the 
water  supply  is  sewage,  human  and  animal  excreta,  which 
are  commonly  deposited  upon  the  ground,  thrown  into 
waters,  and  are  well  mixed  with  almost  all  waters  on  the 
surface,  as  well  as  near  the  subsurface  of  the  ground.  Hence 
it  is  nearly  always  the  case  that  all  sources  of  water  supply 
are  more  or  less  contaminated  with  sewage  matter. 

As  the  pathogenic  microbes  of  typhoid  fever,  cholera,  dys- 
entery, various  gastro-intestinal  diseases  are  commonly  found 
in  the  excreta  of  diseased  persons,  the  pollution  of  drinking 
water  with  such  excreta  is  clearly  the  cause  of  the  "water- 
borne  diseases"  and  epidemics. 


SOURCE  OF  PUBLIC  WATER  SUPPLY  113 

Sources  of  Public  Water  Supply. — The  common  sources  of 
;^ater  supply^in  small  communities,  rural  locations,  and  indi- 
vidual farms  are  obviously  inadequate  for  large  communities 
and  big  cities,  with,  their  hundreds  of  thousands  and  millions 
of  population. 

Large  fresh-water  lakes  and  rivers  on  which  cities  are  situ- 
ated have  at  times  been  relied  on  for  water  supply,  but  as  the 
same  rivers  and  lakes  have  been  commonly  used  as  dump- 
grounds  for  waste  from  factories,  and  for  the  huge  quantities 
of  sewage  matter  produced  by  those  cities,  it  is  evident  that 
such  a  public  water  supply  becomes  a  menace  to  the  health 
of  the  population  by  the  great  contamination  of  the  water 
and  by  consequent  increase  in  the  death  rate  from  typhoid 
fever  and  other  water-borne  diseases  in  those  cities.  This 
was  actually  the  case  in  Chicago,  Lawrence,  Mass.,  Phila- 
delphia, and  many  other  cities  which  received  their  drinking 
water  from  such  sources,  and  in  which  cities  the  increasing 
typhoid  fever  mortality  compelled  them  to  seek  for  better 
methods  of  public  water  supply. 

The  public  water  supply  sources  relied  on  by  many  cities 
are  the  natural  or  artificial  water  -  reserv-airs,  jot  collections 
of  surface  waters,  rivers,  streams,  lakes,  and  ponds,  which 
may  be  at  some  distance  from  the  towns,  and  which  may  be 
fed  by  natural  springs  and  by  the  natural  rainfall.  Such 
sources  may  be  at  great  distances  from  the  towns  which  they 
supply,  as  is  the  case  with  the  Croton  water  supply  of  New 
York  City,  and  still  more  with  the  newly  projected  Catskill 
watersheds  and  ducts,  which  are  hundreds  of  miles  from  the 
city  they  are  to  supply. 

The  construction  and  maintenance  of_  the.  water  sheds, 
Igseryoirs,  dams,  aqueducts,  and  other  parts  of  the  public 
water  supply  system  are  within  the  province  of  the  sanitary 
engineer.  TThe  health  authorities,  however,  of  the  towns  have 
a  direct  interest,  and  it  is  their  duty  to  supervise  the  sanitation 
of  the  watershed  country  and  the  prevention  of  sources  of 
contamination  of  the  supply  system.  Such  a  prevention  of 
contamination  demands  the  proper  disposal  of  the  sewage 
of  the  places  about  the  water  supply  sheds  and  the  prevent- 


114  PUBLIC  WATER  SUPPLY 

ing  of  the  employees  and  other  persons  having  charge  of 
the  various  waterworks  from  depositing  their  excreta  in  a 
manner  which  may  pollute  the  surface  near  the  water 
sources. 

But  the  most  rational,  the  most  effective,  and  therefore  the 
most  hygienic  method  of  insuring  a  pure  water  supply,  aside 
from  the  already  noted  means,  is  the  public  water  purification. 

Public  Water  Purification. — ^The  means  for  purification  of 
public  water  supplies  are  the  following:  storage  and  sedi- 
mentation, chemical  treatment,  and  filtration. 

Sedimentation. — ^A  part  of  the  impurities  in  the  water  may 
be  removed  therefrom  by  storing  the  water  in  basins  where 
the  suspended  matter  sinks  by  the  action  of  gravity,  and  in 
the  process  of  settling  entangles  other  impurities,  as  well  as 
some  of  the  bacteria  in  the  water.  In  order  to  get  good  results 
the  basins  must  be  shallow,  the  water  left  undisturbed,  and 
the  accumulated  sediment  removed  from  time  to  time.  No 
complete  reliance  can  be  put  on  this  method  of  water  purifi- 
cation, as  it  does  not  guarantee  a  germ-free  water. 

Chemical  Purification. — The  sedimentation  of  water  in  the 
basins  may  be  hastened  by  the  addition  to  the  water  of  cer- 
tain chemicals,  which  act  as  coagulants  and  form  precipitates, 
entangling  the  organic  impurities  and  bacteria,  thus  freeing 
the  water  from  a  large  part  of  them.  The  sulphate  of 
aluminum,  or  alum  (half  a  grain  to  the  gallon),  is  used  as 
such  coagulants.  Other  chemicals  used  for  water  purification 
are  chlorine,  bromine,  copper  sulphate,  metallic  iron,  ozone, 
sodium  bisulphate,  etc. 

Neither  sedimentation,  nor  chemical  purification  is  prac- 
ticable for  large  water  supplies,  nor  are  they  free  from  many 
objections. 

Filtration. — The  only  method  which  has  proved  successful 
in  providing  a  pure  water  supply  is  filtration. 

Filtration  on  a  large  scale  was  first  introduced  by  John 
Simpson,  in  London,  in  1829,  and  it  was  at  first  thought  to 
act  only  mechanically,  but  it  has  since  been  proved  that  its 
action  is  also  largely  biological. 

Filtration  of  large  quantities  of  water  is  accomplished  by 


FILTRATION  115 

means  of  sand  beds  of  large  area,  the  sides  and  bottoms  of 
which  are  concreted,  and  on  the  bottom  of  which  are  placed 
numerous  perforated  and  open  drains  which  are  to  lead  off 
the  filtered  water  into  separate  special  reservoirs.  On  the 
bottom  of  the  filter  areas,  which  are  usually  half  or  an  acre 
in  size,  is  placed  a  layer  of  coarse  gravel,  upon  this  a  layer  of 
finer  gravel,  which  is  then  covered  by  a  layer  of  fine,  sharp 
sand,  several  feet  in  thickness,  the  whole  filtering  medium 
being  from  4  to  6  feet  in  thickness.  The  filter  is  at  first 
filled  from  beneath  so  that  all  air  be  driven  off,  and  the  filter 
area  is  then  filled  to  a  level  of  several  feet  above  the  filter  bed. 
A  filter  of  an  acre  in  area  may  be  made  to  filter  two  to  four 
millions  of  gallons  of  water  in  twenty-four  hours.  Such  fil- 
ters act  not  only  mechanically  in  intercepting  all  suspended 
impurities,  but  the  slimy  sheet  which  soon  covers  the  top 
layer  of  the  sand  acts  biologically  upon  the  water  and  de- 
stroys a  large  number  of  bacteria,  so  that,  it  is  claimed,  the 
water  may  be  freed  from  99  per  cent,  of  its  bacteria,  provided 
,the  rate  of  filtration  is  not  too  rapid  and  the  top  of  the  sand- 
layers  is  scraped  off  half  an  inch  from  the  surface  from  time 
to  time. 

In  cold  climates  such  filters  are  protected  from  freezing 
by  the  provision  of  permanent  covers. 

According  to  Robert  Koch,  a  filtered  water  which  contains 
more  than  100  bacteria  to  the  cubic  centimeter  should  be 
rejected. 

When  the  filtration  of  the  water  is  done,  instead  of  in  large 
filter  beds,  in  iron  or  wood  cylinders  filled  with  coarse  sand, 
and  the  water  is  driven  through  the  cylinders  under  pressure 
and  a  great  deal  faster  than  in  large  filters,  the  process  is 
called  mechanical  filtration.  It  is  usually  assisted  by  appli- 
cation of  alum.  The  whole  process  is  essentially  different 
from  common  sand  filtration,  and  is  not  «»ii'table  to  the  water 
supplies  of  many  cities. 


116    ,  PUBLIC  WATER  SUPPLY 

WATER  INSPECTION. 

An  examination  of  the  quality  and  purity  of  water  foi 
drinking  purposes  is  a  very  complicated  procedure,  requiring 
not  only  expert  sanitary  knowledge,  but  also  a  thorough 
training  in  chemical  and  bacterial  analysis,  and  a  capacity 
for  weighing  and  comparing  all  data  gained  in  order  to  base 
judgment  on  them. 

A  microscopic  and  bacteriological  examination  of  drinking 
water  by  itself  is  of  little  value,  as  a  water  may  be  very  much 
polluted  with  organic  matter  without  necessarily  showing 
the  presence  of  any  pathogenic  bacteria;  nor  is  the  failure 
of  finding  any  pathogenic  bacteria  in  a  sample  of  a  given 
water  a  proof  that  such  water  is  not  contaminated  with 
germs  of  typhoid,  or  cholera,  etc.  A  bacteriological  exami- 
nation is,  therefore,  valuable  only  when  positive  results 
are  obtained,  and  in  conjunction  as  an  aid  to  a  sanitary 
and  chemical  examination. 

Nor  is  a  chemical  examination  of  a  water  sufficient  by  itself 
to  give  sufficient  data  for  basing  a  judgment  on  the  quality 
of  the  water,  for  a  water  may  contain  chlorine,  nitrates 
and  nitrites,  and  ammonia,  and  still  not  be  very  bad;  and 
the  presence  of  one  or  more  chemical  ingredients  may  be 
due  to  so  many  different  causes  that  a  qualitative  opinion 
may  not  be  possible  to  be  based  upon  these  data  alone. 

A  sanitary  inspection  of  the  sources  of  a  given  water,  of 
the  surroundings  and  mode  of  formation  of  the  water  col- 
lection, is  comparatively  of  more  importance  than  any  other 
•  examination;  and  a  chemical  examination  of  a  water  must 
be  made  after  a  thorough  sanitary  inspection  of  the  water 
supply,  and  then  only  would  be  valuable  as  a  procedure 
for  the  judging  of  the  purity  and  quality  of  the  water. 

The  sanitary  inspection  of  the  sources  of  the  water  supply 
consists  in  an  examination  of  the  place  where  the  water  comes 
from,  the  place  where  it  is  collected  and  stored,  and  the 
possible  sources  of  organic  contamination  in  the  immediate 
neighborhood  of  the  water. 


WATER  INSPECTION  117 

The  sanitary  inspection  of  rivers,  lakes,  and  ponds  will 
then  consist  in  the  examination  of  the  sources  of  those 
watercourses,  the  condition  of  the  shores,  the  presence 
of  habitations,  factories,  and  other  settlements  upon  the 
shores,  and  their  polluting  the  water  by  their  waste  matters 
and  sewage;  the  presence  of  considerable  number  of 
cattle  drinking  from  the  watercourses;  the  manner  of  con- 
ducting the  water  from  those  places  to  the  habitations, 
and  many  other  similar  important  subjects. 

The  sanitary  inspection  of  rainwater  supplies  will  limit 
itself  to  an  examination  of  the  storage  and  collection  sur- 
faces and  vessels,  their  covers,  and  the  time  the  water  is 
stored. 

The  sanitary  inspection  of  wells  consists  in  the  examina- 
tion of  the  probable  sources  of  the  water  within  the  wells, 
their  depth,  shallow  or  deep,  the  proximity  of  stables, 
manure  pits,  cesspools,  privies,  etc.,  to  the  wells,  and  the 
possibility  of  pollution  of  the  well  water  by  their  drainage; 
the  proximity  of  cattle  pens,  hog  pens,  and  other  animal 
habitations;  the  form  and  depth  of  the  well  as  well  as  the 
depth  of  the  water  therein;  the  method  of  covering  the 
walls  of  the  well,  also  the  mode  by  which  the  water  is  drawn 
from  the  well,  etc. 

Wliile  it  is  possible  by  the  sanitary  inspection  of  the 
sources  of  the  water  supply  to  judge  of  its  possible  purity  or 
contamination,  a  positive  proof  of  pollution  may  be  gained 
only  by  a  chemical  examination. 

Besides  a  physical  examination  of  the  color,  turbidity, 
reaction,  odor,  and  total  amount  of  solids  in  the  water, 
we  find  by  a  chemical  examination  the  degree  of  hardness, 
the  amounts  of  chlorine,  ammonia,  nitrates,  nitrites,  other 
compounds,  gases,  and  acids,  as  well  as  the  presence  of 
metals. 

In  collecting  samples  of  the  water  for  chemical  examination 
care  must  be  taken  to  use  clean  bottles  and  to  perform 
the  examination  as  soon  after  the  collection  of  the  samples 
as  possible.  Glass  bottles  containing  half  a  gallon  are 
commonly   employed  for  taking  samples,   and  the  bottles 


118  PUBLIC  WATER  SUPPLY 

are  rinsed  and  washed  in  the  water  to  be  examined  and 
closed  by  glass  stoppers. 

The  color  of  the  water  is  judged  from  its  appearance  by 
putting  it  into  an  18-  or  24-inch  glass  tube  and  comparing  the 
sample  with  a  similar  tube  filled  with  distilled  water.  Good 
waters  are  either  bluish  or  grayish.  Green,  brown,  or  yellow 
waters  are  suspicious. 

The  turbidity  of  the  water  may  be  examined  in  the  same 
way,  and  a  standard  of  turbidity  is  indicated  by  the  im- 
possibility to  read  printed  matter  through  the  water-filled 
glass  tube. 

The  odor  of  the  water  is  more  perceptible  when  the  water 
is  heated. 

The  total  amount  of  solids  is  determined  by  evaporation 
and  weighing  of  the  residue. 

The  many  qualitative  and  quantitative  tests  of  various 
ingredients  recjuire  expert  chemical  knowledge  and  experience 
for  understanding,  and  cannot  be  gone  into  here. 

The  significance  of  the  various  ingredients  in  an  examined 
water  is  a  matter  of  expert  consideration,  and  depends  on 
the  quantities  of  the  ingredients  and  on  other  factors.  The 
following  brief  remarks  may  be  of  benefit: 

Chlorine. — Sewage  contamination  is  always  followed  by 
presence  of  chlorine  in  chlorides,  although  chlorine  may 
be  contained  in  water  which  is  not  contaminated  by  sewage, 
but  may  be  due  to  deposits  of  salts,  or  to  sea  water.  A 
marked  presence  of  chlorine,  however,  should  be  regarded 
as  suspicious  of  sewage. 

The  presence  of  considerable  amounts  of  free  ammonia, 
as  well  as  albuminoid  ammonia  point  to  the  conclusion  that 
the  water  is  contaminated  by  organic  matter,  sewage,  or 
urine. 

Nitrites  and  Nitrates. — Organic  matter  contains  nitro- 
genous compounds,  which  upon  undergoing  chemical 
changes  and  oxidation  produce  nitric  and  nitrous  acids. 
The  presence  of  the  latter,  therefore,  indicates  contamina- 
tion with  organic  matter.  Pure  water  is  free  from  nitrites 
and    should     contain    but    few    traces    of    nitrates.     The 


QUESTIONS  119 

very  presence  of  nitrites  is  suspicious,  while  the  amount 
of  nitrates  must  be  marked  before  the  water  may  be  classed 
as  suspicious.  Nitrates  are  generally  due  to  oxidation  of 
organic  matter  of  animal  origin.  Nitrites  are  due  to  sewage 
coDtamination.  They  indicate  more  recent  contamination, 
and  are  more  dangerous. 

Metals. — Except  for  traces  of  iron  which  any  good  water 
may  show,  no  metal  should  be  found  in  water. 

As  a  rule,  not  without  its  exceptions,  a  water  which  is 
contaminated  but  recently  with  sewage  matter  will,  upon 
chemical  examination,  show  a  marked  presence  of  chlorine, 
ammonia,  nitrates,  and  nitrites.  In  order,  however,  to 
judge  scientifically  it  will  be  necessary  to  make  thorough 
qualitative  as  well  as  quantitative  tests,  in  conjunction 
with  a  sanitary  inspection  of  the  water  supply,  as  well  as 
bacteriological  tests. 

QUESTIONS, 

Name  the  parasitic  ova  that  may  be  found  in  water,  and  state  their 
effects  on  health. 

What  pathogenic  bacteria  may  be  found  in  water? 

What  are  the  special  relations  of  typhoid  and  cholera  infection  and  drink- 
ing water? 

Name  the  various  sources  of  public  water  supply. 

What  are  the  principal  dangers  to  the  sources  of  public  water  supply? 

What  are  the  methods  of  purification  of  public  water  supply? 

Describe  the  advantages  and  process  of  sand  filtration. 

Describe  a  system  of  mechanical  filtration. 

What  are  the  methods  of  sanitary  inspection  of  water? 

What  is  the  significance  of  the  various  ingredients  found  in  water? 


CHAPTER  VI. 
FOOD  SUPPLY. 

Public  food  supply  and  public  health  are  intimately  con- 
nected because  of  the  dangers  to  health  of  impure  foods,  and 
the  subject  is  therefore  a  part  of  public  hygiene. 

The  chemical  constituents  of  the  various  foods,  the  theory 
and  practice  of  nutrition,  and  the  subject  of  dietetics  belong 
to  the  domain  of  chemistry,  physiology,  and  individual 
hygiene,  while  public  hygiene  deals  with  the  effects  of 
impure  food  supplies  from  public  health. 

"  Food  is  that  which,  when  taken  into  the  body,  builds  tissue 
or  yields  energy."  Everything  is  therefore  food  which  may 
be  used  for  the  purpose  of  replacing  the  loss  due  to  the  wear 
and  tear  of  the  cells  of  the  body  or  of  supplying  heat  and 
energy  to  the  body,  or  of  storing  up  such  energy  for  future 
use. 

The  sources  of  human  food  are  the  vegetable,  mineral,  and 
animal  kingdoms.  Certain  minerals  and  a  large  number  of 
cereals,  roots,  vegetables,  fruits  and  nuts  are  used  either  in 
their  natural  state  or  specially  prepared  and  somewhat 
modified  by  art  and  science.  The  flesh  of  a  large  number 
of  animals  is  used  as  human  food  when  specially  prepared 
and  modified  by  man. 

All  food  contains,  beside  nutrients  and  waste  matter,  also 
a  greater  or  smaller  percentage  of  w^ater. 

Chemical  Composition. — In  their  final  analysis  all  foods 
contain  the  elements — carbon,  hydrogen,  oxygen,  nitrogen, 
sulphur,  sodium,  potassium,  calcium,  magnesium,  etc.  Most 
of  the  foods  taken  into  the  body,  however,  are  derived  from 
the  organic  world;  the  only  foods  taken  from  the  inorganic 
world  are  mineral  matter  and  water. 

The  first  subdivision  of  food  is  therefore  into  organic  and 
inorganic. 
( 120 ) 


MEAT  FOODS  121 

The  mineral  substances  used  for  food  are  sodium,  potas- 
sium, magnesium,  chlorine,  sulphur,  phosphorus,  iron,  silica, 
fluorine,  iodine,  etc. 

The  water  and  mineral  substances  used  for  food  are  taken 
either  in  their  natural  state  or  in  combination  with  organic 
foodstuffs. 

Organic  foods  are  divided  into  two  main  groups :  nitrogen- 
ous and  non-nitrogenous. 

T,T.^  ,       .   ■  N  /  White  of  eggs,  cxird  or  casein  of  milk ;  lean  meat. 

Nitrogenous  (protem)  |      gj^^^^  ^f  ^^^^^^  ^^^ 

T.r         .,  I  Carbohydrates:  Sugar,  starch,  etc. 

Non-mtrogenous  j  Fats:  Animal,  vegetable. 

Estimates  of  Food  Values. — The  use  of  food  produces  energy 
and  heat.  This  heat  may  be  measured  and  serves  as  criterion 
of  the  heat  and  food  values.  The  measure  of  heat  is  in 
"Calories."  A  calorie  is  the  amount  of  heat  required  to 
raise  1  kilogram  of  water  1°  Centigrade.  It  has  been  found 
out  that: 

1  gram  of  protein  gives 4.1  available  calories 

1  gram  of  carbohydrates 4.1  "  " 

1  gram  of  fat 9.3  "  " 

By  the  aid  of  this  table  it  is  possible  to  calculate  the  fuel 
value  in  calories  per  certain  weight  of  food. 

For  instance  the  composition  of  milk  is  protein,  3  per  cent.; 
sugar,  5  per  cent. ;  fat,  4  per  cent.  The  number  of  calories 
represented  by  100  grams  of  milk  will  be  as  follows: 

Protein 3x4.1=12.3 

Fat 4  X  9 . 3  =  37 . 2 

Carbohydrates 5x4.1=  20. 5 

Total =70  calories 

The  special  dangers  to  health  of  meats  and  of  milk  justify 
us  in  treating  these  foods  at  length,  while  but  briefly  alluding 
to  the  others. 

I.   MEAT   FOODS. 

The  hygiene  of  meat  foods  may  be  considered  according  to 
the  following  subdivisions: 


122  '  FOOD  SUPPLY 

Dangers  to  Health:  Infection  by  entozoa,  infection  by 
bacteria,  toxins,  and  ptomains. 

Etiology :  Diseases  of  the  animals,  condition  of  the  animals, 
postmortem  changes,  postmortem  infection,  adulteration. 

Prophylaxis:  Hygiene  of  the  food  animals:  meat  inspec- 
tion, antemortem  and  postmortem;  hygiene  of  place  and 
persons;  preservation,  sanitary  supervision  of  manufacture, 
etc. 

Dangers  to  Health. — The  dangers  to  health  from  the  inges- 
tion of  flesh  foods  are  due  to  infection  by  entozoa,  infections 
by  bacteria,  and  to  the  action  of  toxins  and  ptomains. 

The  parasitic  diseases  due  to  meat  are  caused  by  (1)  infec- 
tion by  tapeworms,  (2)  infection  by  trichina,  and  (3)  infection 
by  echinococci. 

Tapeworm. — The  two  principal  species  of  tapeworm  found 
in  man  which  are  due  to  meat  infection  are  the  toenia  sagi- 
nata  and  the  toenia  solium;  the  former  is  due  to  infection  by 
"measly"  beef,  the  latter  by  "measly"  pork. 

The  ^'  cysticercus  cellulosce"  is  the  larval  form  of  the  tcBJiia 
solium,  and  is  found  in  hogs,  in  which  it  appears  as  minute 
bladder  worms,  encased  in  little  cysts  w^hich  are  found  in  the 
intestines,  muscular  fibers,  brain,  liver,  and  other  parts,  and 
especially  under  the  tongue,  where  it  may  readily  be  recog- 
nized. The  cysticercus  is  derived  from  the  segment  and 
egg  of  the  icenia  solium,  which  are  passed  from  the  human 
intestine,  ingested  by  the  hog,  and  on  reingestion  by  man 
are  redeveloped  into  tenia. 

The  cysticercus  bovis  is  the  lars^al  form  of  the  t(B7iia  sagi- 
nata  of  man,  and  is  found  in  the  intermuscular  fibers  and 
connective  tissue  of  cattle. 

The  trichina  spiralis  is  a  parasite  found  mostly  in  the  mus- 
cular fibers  of  pork,  in  the  form  of  minute  spiral-form  worms, 
which  are  encapsulated,  but  may  be  recognized  with  the  naked 
eyes  as  white  specks.  The  ingestion  of  pork  infected  by 
trichina  causes  in  man  the  disease  called  "trichinosis,"  an 
acute  disease  due  to  the  presence  of  the  trichina  in  the  mus- 
cular fibers,  and  the  symptoms  of  which  resemble  typhoid 
fever.     The  disease  is  often  fatal. 


MEAT  FOODS  123 

Echinococcus  sometimes  infects  sheep,  and,  rarely,  cattle, 
and  the  meat  causes  in  man  the  hydatid  diseases.  Originally 
the  infection  comes  from  the  tcenia  echinococcus  found  in  dogs. 

Meat  Infection  by  Bacteria. — Pathogenic  bacteria  may  be 
found  in  the  flesh  of  animals,  and  is  capable  of  producing 
disease  in  man  on  eating  the  infected  meat.  The  patho- 
genic bacteria  may  originate  in  the  diseased  condition  of 
the  live  animals  suffering  from  the  infectious  diseases,  or  the 
pathogenic  germs  may  gain  entrance  into  the  meat  of  healthy 
animals  through  infection  by  contact,  etc.,  after  killing. 

The  diseases  of  animals  infectious  to  man  which  are  caused 
by  pathogenic  bacteria  and  which,  it  is  claimed,  may  be 
transmitted  through  their  meat  to  man,  are  the  following: 
Tuberculosis,  pleuropneumonia,  foot  and  mouth  disease, 
cattle  plague,  anthrax,  glanders,  malignant  edema,  erysipelas, 
actinomycosis,  typhoid  fever,  cholera,  pyemia,  septicemia, 
tetanus,  sheep-pox,  Texas  fever,  etc. 

Toxins  and  Pto mains. — Certain  meat  causes  on  ingestion 
toxic  symptoms.  These  symptoms  are  due  to  substances  in 
the  meat  which  are  toxic,  or  to  bacterial  products  of  decom- 
position, called  "ptomains."  The  symptoms  resemble  those 
of  severe  gastro-intestinal  inflammation,  and  may  be  fatal. 
The  bacillus  botulinus  and  others  have  been  regarded  as 
causing  some  of  the  toxic  influences  of  certain  meats. 

The  virulence  of  the  intoxication  by  meat  differs  according 
to  the  condition  of  meat,  the  manner  of  preparation,  the 
quantity  ingested,  and  the  individual  idiosyncrasies  of  the 
victim. 

The  most  frequent  cases  of  intoxication  are  caused  by  the 
eating  of  "prepared  meats,"  such  as  chopped  meats,  sausages, 
canned,  "potted,"  and  "deviled"  meats,  etc. 

The  causes  of  the  unfitness  of  meat  for  food  may  be  due  to : 
(1)  Diseases  of  animals;  (2)  unfit  condition  of  living  animals; 
(3)  postmortem  changes;  (4)  infection  of  the  meat  by  per- 
sons or  by  places  of  manufacture,  sale,  etc. ;  (5)  adulteration. 

The  diseases  of  food  animals  which  render  their  meat 
totally  or  partly  unfit  for  food  have  been  enumerated  above, 
and  will  be  mentioned  again  in  the  section  on  meat  inspection. 


124  FOOD  SUPPLY 

The  condition  of  the  food  animals  which  may  render  their 
meat  unfit  for  food  are  the  following: 

1.  Death  of  animal  from  age,  disease,  or  accident. 

2.  Moribund  condition  from  injury,  drugs,  overwork, 
fright,  overdriving,  etc. 

3.  Immature  animals,  unborn  calves  and  lambs,  and  such 
as  are  in  the  first  few  weeks  of  life. 

4.  Artificial  conditions  and  treatment  of  the  carcass  by 
blowing  up  (blown  veal),  coloring,  etc, 

Postmortem  Changes. — The  temperature  and  moisture  and 
substance  of  the  slaughtered  carcass  make  it  the  best  medium 
for  the  development  and  life  of  the  swarming  microorganisms 
present  in  the  meat  and  such  as  may  gain  access  later.  The 
resulting  decomposition  and  organic  changes  are  bound  to 
deteriorate  the  flesh  so  as  to  render  it  unfit  for  food  unless 
bacterial  action  is  inhibited;  that  is,  unless  the  meat  is  put 
into  a  condition  rendering  the  development  of  bacteria  and 
putrefaction  unfavorable.  The  rapidity  with  which  the 
meat  deteriorates  depends  on  the  condition  of  the  animal 
from  which  it  is  obtained,  the  cleanliness  of  the  process  of 
preparation,  and  the  place  in  which  it  is  kept. 

Infection  by  Persons  and  Places. — In  addition  to  all  the 
foregoing  sources  of  deterioration,  meat  may  be  directly  in- 
fected with  pathogenic  and  other  bacteria  by  the  many  per- 
sons who  handle  and  who  take  part  in  the  slaughtering, 
skinning,  dressing,  cutting,  manufacturing,  packing,  etc., 
of  the  meat  and  its  products. 

The  infection  of  the  food  may  also  be  received  from  the 
various  places  through  which  the  meat  must  pass  in  the 
various  processes  of  manufacture. 

Adulteration. — By  "adulteration"  is  meant  the  changing, 
or  a-ltering  of  the  normal  composition,  constitution,  or  ap- 
pearance of  the  food.  Adulteration  is  often  dangerous  to 
health  by  the  changes  in  the  normal  constitution  of  the  food, 
or  it  may  be  simply  fraudulent  in  substituting  partly  or 
wholly  less  expensive  substances  for  the  more  costly. 

Meat  adulterations  may  consist  in : 

1.  Addition  of  foreign  substances  reducing,  lowering,  or 
injuring  the  quality  of  the  food. 


MEAT  FOODS  125 

2.  Partial  or  entire  substitution  of  an  inferior  substance. 

3.  Extraction  of  some  of  the  valuable  substance  from  the 
meat. 

4.  Coloring,  coating,  or  otherwise  changing  the  appear- 
ance of  the  food,  whereby  poor  quality  is  concealed,  or  it  is 
made  to  look  better  than  it  is. 

5.  Addition  of  some  foreign  substance  to  "preserve"  it. 
Prophylaxis. — ^The  means  of  preventing  the  injurious  effects 

of  unfit,  bad,  and  infected  meats  are  the  following: 

1.  Sanitary  care  for  food  animals. 

2.  Meat  inspection  (antemortem  and  postmortem). 

3.  Sanitation  of  places  and  persons. 

4.  Preservation,  or  destruction  of  infective  agents. 

5.  Sanitary  supervision  of  manufacture  and  sale,  etc. 
Sanitary  Care  for  Food  Animals. — The  housing,  feeding,  and 

care  of  the  domestic  animals  which  are  to  be  rendered  as 
food  is  of  much  importance  to  their  health,  and  conse- 
quently to  the  health  of  the  persons  for  whose  food  they  are 
intended. 

The  construction  of  cattle  pens,  stables,  barns,  and  other 
places  intended  for  keeping  animals  must  follow  the  rules 
guiding  all  construction  of  shelters  from  rain,  storms,  and 
extremes  in  climates. 

Abundant  sources  of  natural  light,  in  the  form  of  windows 
and  skylights,  must  be  provided  in  every  stable,  barn,  etc. 

From  7000  to  10,000  cubic  feet  of  air  are  needed  per 
hour  for  cows  and  horses,  and,  therefore,  the  change  of  air  in 
the  barns  and  stables  must  be  frequent  and  abundant. 

Ventilation  of  stables,  etc.,  may  be  had  through  openings  in 
windows,  skylights,  or  special  inlets  and  outlets  designed  for 
the  purpose. 

In  very  cold  places  the  stables,  etc.,  should  be  artificially 
heated  during  winter. 

Plenty  of  pure  water  should  be  provided  for  drinking  pur- 
poses, as  well  as  for  washing  and  cleansing. 

The  drainage  of  the  stables,  etc.,  must  be  carefully  planned, 
so  as  to  immediately  remove  all  liquid  urine  and  manure 
from  under  the  stall  and  flush  away  all  liquids  into  properly 
trapped  and  sewer-connected  drains. 


126  FOOD  SUPPLY 

The  walls  and  ceilings  should  be  constructed  of  some  non- 
absorbent  material  easily  cleaned  and  washed,  while  the 
floors  must  invariably  be  made  of  cement,  concrete,  or  tile, 
or  stones  set  in  cement,  and  the  floor  be  properly  graded,  so 
as  to  drain  all  liquids  into  the  drain,  while  at  the  foot  of  every 
stall  an  iron  valley  drain,  properly  covered,  provided  for  the 
draining  of  all  urine  and  liquids. 

All  manure  and  refuse  should  be  collected  several  times 
daily,  packed  in  proper  receptacles,  and  removed  from  the 
premises. 

The  animals  need  daily  exercise,  fresh  air,  and  should  be 
washed  and  scrubbed  at  periodical  intervals. 

Daily  grazing  in  fields  during  milder  weather  is  neces- 
sary for  the  animal's  health,  as  well  as  the  provision  for 
its  proper  feeding  with  cornmeal  and  other  appropriate 
foods. 

Inspection  and  examination  by  competent  veterinarians  is 
periodically  necessary  to  discover  incipient  disease  and  to 
isolate  diseased  cattle  from  the  herd. 

Tuberculin  tests  should  be  made  at  periodical  intervals, 
and  all  diseased  cattle  condemned  and  destroyed. 

Care  must  also  be  taken  of  the  animals  during  their  trans- 
portation in  cars,  in  the  cattle  pens  where  they  are  exposed 
for  sale,  as  well  as  in  the  pens  where  they  are  kept  before 
slaughter. 

The  sanitation  of  packing  houses  and  factories  where  the 
meat  is  transformed  into  the  various  articles  of  commerce  is 
supervised  by  federal,  state,  and  municipal  authorities,  and 
the  following  extracts  from  Regulation  11  of  the  Federal 
Meat  Inspection  Law  (B.  A.  I.,  No.  137)  will  illustrate  the 
principal  points: 

"(a)  Ceilings,  side  walls,  pillars,  partitions,  etc.,  shall  be 
frequently  whitewashed  or  painted,  or,  where  this  is  imprac- 
ticable, they  shall,  when  necessary,  be  washed,  scraped,  or 
otherwise  rendered  sanitary.  ,  .  .  All  floors  upon  which 
meats  are  piled  during  the  process  of  curing  shall  be  so  con- 
structed that  they  can  be  kept  in  a  clean  and  sanitary  condi- 
tion, and  such  meats  shall  also  be  kept  clean. 


MEAT  FOODS  127 

"(b)  All  trucks,  drays,  and  other  receptacles,  all  chutes, 
platforms,  racks,  tables,  etc.,  and  all  knives,  saws,  cleavers, 
and  other  tools,  and  all  utensils  and  machinery  used  in  mov- 
ing, handling,  cutting,  chopping,  mixing,  canning,  or  other 
process  shall  be  thoroughly  cleansed  daily,  if  used. 

"(c)  The  aprons,  smocks,  or  other  outer  clothing  of  em* 
ployees  who  handle  meat  in  contact  with  such  clothing 
shall  be  of  a  material  that  is  readily  cleansed,  and  shall  be 
cleansed  daily,  if  used.  Employees  who  handle  meats  or 
meat  food  products  shall  be  required  to  keep  their  hands 
clean. 

"(d)  All  toilet  rooms,  urinal,  and  dressing  rooms  shall  be 
entirely  separated  from  compartments  in  which  carcasses  are 
dressed  or  meat  foods  are  cured,  stored,  packed,  handled,  or 
prepared.  They  shall  be  sufficient  in  number,  ample  in  size, 
and  fitted  with  modern  lavatory  accommodations,  including 
toilet  paper,  soap,  running  water,  towels,  etc.  They  shall  be 
properly  lighted,  suitably  ventilated,  and  kept  in  a  sanitary 
condition. 

"(e)  The  rooms  and  compartments  in  which  meat  and  meat 
products  are  prepared,  or  otherwise  handled,  shall  be  lighted 
and  ventilated  in  a  manner  acceptable  to  the  inspector  in 
charge,  and  shall  be  so  located  that  odors  from  toilet  rooms, 
catch  basins,  casing  departments,  tank  rooms,  hide  cellars, 
etc.,  do  not  permeate  them. 

"(f)  Persons  affected  with  tuberculosis  or  other  communi- 
cable disease  shall  not  be  knowingly  employed  in  any  depart- 
ment of  the  establishments  where  carcasses  are  dressed, 
meats  handled,  or  meat  food  products  prepared,  and  any 
employee  suspected  of  being  so  affected  shall  be  so  reported 
by  the  inspector  in  charge. 

"(j)  Meats  and  meat  food  products  intended  for  rendering 
into  edible  products  must  be  prevented  from  falling  upon  the 
floor,  while  being  emptied  into  the  tanks,  by  the  use  of  some 
device,  such  as  a  metal  funnel. 

"(I)  Carcasses  or  parts  thereof  inflated  with  air  blown  from 
the  mouth  shall  not  be  passed. 

"(w)  Carcasses  dressed  with  skewers  that  have  been  held  in 
the  mouth  shall  not  be  passed." 


128  FOOD  SUPPLY 

The  foregoing  are  some  of  the  rules  to  render  the  manu- 
factm-ing  of  meat-food  products  more  sanitary  and  to  keep 
the  personnel  and  places  in  a  sanitary  condition. 

II.  ANTEMORTEM  AND   POSTMORTEM  MEAT 
INSPECTION. 

The  following  is  an  extract  from  the  official  Regulations 
of  the  United  States  Department  of  Agriculture  as  embraced 
in  Regulations  13,  14,  15: 

"Antemortem  Examination  and  Inspection  of  Meat. — ^An  ante- 
mortem  examination  and  inspection  shall  be  made  of  all  cattle, 
sheep,  swine,  and  goats  about  to  be  slaughtered  before  they 
shall  be  allowed  to  enter  an  establishment  at  which  inspection 
is  maintained.  Said  examination  and  inspection  shall  be 
made  in  the  pens,  alleys,  or  chutes  of  the  establishment  at 
which  the  animals  are  about  to  be  slaughtered.  The  pro- 
prietors of  the  establishments  at  which  the  said  antemortem 
inspection  is  conducted  shall  provide  satisfactory  facilities 
for  conducting  said  inspection  and  for  separating  and  holding 
apart  from  healthy  animals  those  showing  symptoms  of  dis- 
ease. 

"All  animals  showing  symptoms  or  suspected  of  being 
affected  with  any  disease  or  condition  which,  under  these 
regulations,  would  probably  cause  their  condemnation  when 
slaughtered,  shall  be  marked  by  affixing  to  the  ear  or  tail  a 
metal  tag. 

"All  such  animals,  except  as  hereinafter  provided,  shall  be 
slaughtered  separately,  either  before  regular  slaughter  has 
commenced  or  at  the  close  of  the  regular  slaughter,  and  shall 
be  duly  identified  by  a  representative  of  the  establishment  to 
the  inspector  on  duty  on  the  killing  floor  before  the  skins  are 
removed  or  the  carcasses  opened  for  evisceration, 

"Animals  which  have  been  tagged  for  pregnancy  and  which 
have  not  been  exposed  to  any  infectious  or  contagious  disease 
are  not  required  to  be  slaughtered,  but  before  any  such  animal 
is  removed  from  the  establishment  the  tag  shall  be  detached 


MEAT  INSPECTION  129 

by  a  Department  employee  and  returned  with  his  report  to 
the  inspector  in  charge, 

"If  any  pathological  condition  is  suspected  in  which  the 
question  of  temperature  is  important,  such  as  Texas  fever, 
anthrax,  pneumonia,  blackleg,  or  septicemia,  the  exact  tem- 
perature should  be  taken.  Due  consideration,  however, 
must  be  given  to  the  fact  that  extremely  high  temperatures 
may  be  found  in  otherwise  normal  hogs  when  subjected  to 
exercise  or  excitement,  and  a  similar  condition  may  obtain 
to  a  less  degree  among  other  classes  of  animals.  Animals 
commonly  termed  "downers,"  or  crippled  animals,  shall  be 
tagged,  as  provided  for  in  Regulation  20,  in  the  abattoir  pens 
for  the  purpose  of  identification  at  the  time  of  slaughter,  and 
shall  be  passed  upon  in  accordance  with  these  regulations. 

"Postmortem  Inspection  of  Meat  at  Time  of  Slaughter. — The 
inspector  or  his  assistant  shall,  at  the  time  of  slaughter,  make 
a  careful  inspection  of  all  animals  slaughtered.  The  head, 
tail,  thymus  gland,  bladder,  caul,  and  the  entire  viscera,  and 
all  parts  and  blood  used  in  the  preparation  of  meat  food 
products  shall  be  retained  in  such  manner  as  to  preserve 
their  identity  until  after  the  postmortem  examination  has 
been  completed,  in  order  that  they  may  be  identified  in  case 
of  condemnation  of  the  carcass.  Suitable  racks  or  metal 
receptacles  shall  be  provided  for  retaining  such  parts. 

"Carcasses  and  parts  thereof  found  to  be  sound,  healthful, 
wholesome,  and  fit  for  human  food  shall  be  passed  and 
marked  as  provided  in  these  regulations. 

"Should  any  lesion  of  disease  or  other  condition  that  would 
probably  render  the  meat  or  any  organ  unfit  for  food  pur- 
poses be  found  on  postmortem  examination,  such  meat  or 
organ  shall  be  marked  immediately  with  a  tag,  as  provided 
in  Regulation  27.  Carcasses  which  have  been  so  marked 
shall  not  be  washed  or  trimmed  unless  such  washing  or  trim- 
ming is  authorized  by  the  inspector. 

"Disposal  of  Diseased  Carcasses  and  Organs. — The  carcasses 

or  parts  of  carcasses  of  all  animals  which  are  slaughtered  at 

an  establishment  where  inspection  is  maintained,  and  which 

are  found  at  time  of  slaughter  or  at  any  subsequent  inspection 

9 


130  FOOD  SUPPLY 

to  be  affected  with  any  of  the  diseases  or  conditions  named 
below  shall  be  disposed  of  according  to  the  section  of  this 
regulation  pertaining  to  the  disease  or  condition.  It  is  to  be 
understood,  however,  that  owmg  to  the  fact  that  it  is  imprac- 
ticable to  formulate  rules  covering  every  case,  and  to  designate 
at  just  what  stage  a  process  becomes  loathsome  or  a  disease 
noxious,  the  decision  as  to  the  disposition  of  all  carcasses, 
parts,  or  organs  not  specifically  covered  by  these  regulations 
shall  be  left  to  the  veterinary  inspector  in  charge.  Carcasses 
found,  before  evisceration  has  taken  place,  to  be  affected  with 
an  infectious  or  contagious  disease,  including  tuberculosis, 
shall  not  be  eviscerated  at  the  regular  killing  bed  or  bench, 
but  shall  be  taken  to  the  retaining  room,  or  other  specially 
prepared  place,  separate  from  other  carcasses,  and  there 
opened  and  examined. 

III.    MEAT   PRESERVATION. 

Characteristics  of  Good  Meat. — Good  meat  is  uniform  in 
color,  neither  too  red  nor  too  pale,  firm  and  elastic  to  the 
touch,  moist  but  not  wet;  does  not  pit,  nor  crackle  on 
pressure,  and  has  a  marbled  appearance.  It  is  free  from 
unpleasant  odor,  its  juices  slightly  redden  litmus  paper,  the 
fat  is  firm  and  does  not  run.  Beef  is  bright  red,  more  marbled 
than  any  other  meat.  Veal  is  pale  and  less  firm  to  the  touch. 
Mutton  is  dull  red,  firm,  and  its  fat  white  or  yellowish.  Horse 
meat  is  coarse  in  texture,  dark  in  color,  without  layers  of  fat 
in  the  muscles;  the  fat  is  yellowish  and  runs  down  in  drops 
when  the  carcass  is  hung  up,  and  has  a  peculiar  sweetish 
odor  and  taste. 

Preservation  of  Meat. — ^To  preserve  meats  from  undergoing 
the  postmortem  putrefactive  changes  due  to  development  of 
bacteria  the  following  conditions  are  necessary:  (1)  Preven- 
tion of  infection  of  the  meat  by  microorganisms  from  places 
and  persons;  (2)  storage  of  meat  under  such  conditions  as  are 
unfavorable  for  the  life  and  development  of  bacteria;  and 
(3)  destruction  of  all  microorganisms  in  the  meats. 

The  first  condition  of  prevention  of  meat  infection  may  be 


MEAT  PRESERVATION  131 

attained  by  rigid  asepsis  and  cleanliness,  as  already  indicated 
in  the  description  of  the  sanitation  of  persons  and  places 
where  the  meat  is  produced  and  rendered  into  food  products. 

Storage  of  Meat. — ^The  conditions  which  render  the  life  and 
development  of  organic  germs  difficult,  or  entirely  impossible, 
are  the  following:  cold,  drjTiess,  and  condimental,  or  part 
chemical  preservation. 

The  third  method  is  absolute  destruction  of  all  germs,  i.  e., 
sterilizing  it  by  means  of  heat. 

Cold  storage  of  meat  does  not  kill  bacteria,  but  inhibits  their 
action,  and  keeping  meat  in  cold  storage,  or  freezing  it, 
may  preserve  the  meat  for  quite  a  long  time.  However,  the 
opinion  that  keeping  of  meat  in  cold  storage  may  be  prolonged 
indefinitely  is  wrong,  as  meat  certainly  deteriorates  if  kept 
longer  than  two  or  three  months  at  low  temperature.  Frozen 
meats  deteriorate  very  rapidly  on  being  thawed,  and  have 
been  known  to  produce  toxic  symptoms  on  ingestion.  As 
an  auxiliary  means  of  preservation  for  not  too  prolonged 
periods  cold  is  a  valuable  preservative. 

Drying  of  meat  is  an  old  method  of  preserving  it,  and  may 
be  a  valuable  means  of  preserving  the  meat  fibers,  when 
rendered  very  dry,  or  in  form  of  powders.  The  drying  may 
be  accomplished  in  the  sun,  and  is  very  slow,  or  it  may  be 
done  artificially.     Its  usefulness  is  necessarily  limited. 

Condimental  preservation  of  meat  consists  in  preserving  it  by 
the  aid  of  salt,  sugar,  vinegar,  and  other  condiments,  either 
in  dry  form  (with  salt)  or  by  the  wet  process  (pickling  in 
vinegar,  etc.).  These  condiments  do  not  kill  the  bacteria, 
but  they  effectively  stop  putrefaction  and  may  preserve  cer- 
tain meats  for  long  periods. 

Smoking  meat  renders  it  not  only  comparatively  dry  but  also 
impregnates  it  with  the  creosote  of  the  smoke,  which  serves 
as  a  valuable  means  of  preservation  of  certain  kinds  of  meat. 

None  of  the  above  methods  of  preservation  destroys  para- 
sitic ova,  or  all  the  pathogenic  germs  which  may  be  in  the 
meat,  and,  excepting  cold,  all  of  them  render  the  meat  less 
digestible,  and  somewhat  altered  in  the  texture,  appearance, 
and  taste. 


132  FOOD  SUPPLY 

The  use  of  chemical  preservatives,  such  as  borax,  boracic 
acid,  sulphite  of  soda,  and  others,  is  very  reprehensible,  and 
is  justly  prohibited  by  federal  and  municipal  sanitary  legis- 
lation. 

The  objections  against  chemical  preservatives  of  any  food 
may  be  summed  up  as  follows: 

1.  All  chemicals  used  for  preservation  are  more  or  less 
toxic,  and  their  ingestion  injurious  to  health,  especially  if 
habitually  used. 

2.  By  the  use  of  chemical  artificial  preservatives  inferior 
meats  and  products,  and  mea):s  already  partly  decomposed, 
may  be  so  disguised  as  to  be  sold  as  fresh  and  unspoiled 
products. 

Heat  preservation  of  meat  is  the  only  effective  and  abso- 
lutely reliable  method  of  preservation,  because  it  kills  and 
destroys  all  entozoa  and  pathogenic  germs,  and  thus  renders 
the  product  sterile  and  absolutely  safe. 

For  domestic  use  the  sterilization  of  meat  is  accomplished 
by  roasting,  baking,  or  boiling  it  for  from  fifteen  minutes  to 
an  hour.  For  commercial  use  the  process  of  meat  preservation 
must  be  twofold:  (1)  Destroying  all  germs  by  heat,  and  (2) 
enclosing  the  product  in  hermetically  closed  sterile  vessels, 
in  which  further  infection  is  prevented,  and  thus  the  food 
product  preserved  for  indefinite  periods.  This  process  of 
meat  preservation  consists  in  "canning,"  and  is  accom- 
plished by  the  following  details:  (1)  Selection  of  appropriate 
meat;  (2)  cutting  it  into  appropriate  pieces;  (3)  parboiling, 
or  exposing  the  meat  in  hot  water  under  the  boiling  point  for 
ten  to  twenty  minutes  in  order  to  shrink  it  and  lessen  its  bulk; 
(4)  the  parboiled  meat  is  placed  in  cans  or  tins  filled  with 
salted  soup  or  liquid  and  the  cover  soldered,  except  a  small 
aperture  for  the  escape  of  air;  (5)  the  cans  are  then  placed 
in  boilers  or  steamers  and  subjected  to  high  heat  for  an  hour 
or  two;  (6)  the  openings  left  in  the  cover  of  the  can  are 
closed  and  the  cans  again  subjected  to  a  steam  bath  for  an 
hour  or  more-  according  to  character  of  product. 

Sanitary  Supervision,  Prevention  of  Adulteration  of  Meat, 
etc. — ^The    strict    sanitary    supervision    of   all    the    various 


POULTRY,  GAME,  FISH  FOODS,  AND  OTHER  FOODS     133 

processes  through  which  meat  passes,  from  the  initial  to  the 
final  product,  is  absolutely  necessary  in  order  to  render  the 
food  supply  free  from  dangerous  contaminations  and  infec- 
tion from  the  very  many  sources  to  which  it  is  subjected. 
The  prevention  of  adulteration  by  substitution,  palming  off 
inferior  products  for  superior  ones,  and  by  adulteration  with 
foreign  ingredients,  as  well  as  by  artificial  preservation  by 
means  of  chemicals — all  these  may  be  accomplished  only 
by  a  rigid,  thorough,  scientific,  and  prompt  municipal  and 
federal  inspection  by  qualified  and  competent  medical 
officers. 

IV.  POULTRY,  GAME,  FISH  FOODS,  AND  OTHER  FOODS. 

Poultry  and  Game. — The  flesh  of  all  domestic  fowls,  such  as 
chicken,  turkey,  geese,  duck,  and  of  some  wild  fowls  is  used 
for  human  food. 

Vacher^  gives  the  following  characteristics  of  healthy 
poultry  and  poultry  meats:  "Healthy  poultry  are  active, 
bright,  dry  in  the  eyes  and  nostrils;  their  feathers  are  glossy 
and  elastic,  and  the  combs  and  wattles  are  firm  and  of  bril- 
liant red.  Age  is  indicated  by  duskiness  of  comb  and  gills, 
dulness,  fading,  and  brittleness  of  feathers,  raggedness  of  feet, 
and  size  of  claws.  Good  poultry  should  be  firm  to  the  touch, 
pink  or  yellowish  in  color,  fairly  plump,  should  have  a  strong 
skin,  and  a  fresh,  not  disagreeable  odor.  Stale  poultry  loses 
firmness,  becomes  bluish  in  color,  green  over  the  crop  and 
abdomen;  the  skin  readily  breaks,  and  the  bird  has  a  dis- 
agreeable odor." 

"Drawn"  or  "undrawn"  poultry  is  sold  according  to  whether 
the  internal  organs  are  removed  or  not.  Undrawn  poultry 
decomposes  sooner  on  account  of  intestinal  putrefaction. 

Cold-storage  undrawn  poultry  may  be  dangerous  to  health 
by  its  deterioration,  and  as  there  does  not  seem  to  be  an 
economic  necessity  of  preserving  poultry  for  long  periods, 
as  it  may  be  obtained  at  all  times,  the  practice  is  reprehensible 

1  Food  Inspector's  Handbook. 


134  FOOD  SUPPLY 

The  practice  of  keeping  poultry  or  game  for  a  certain  time 
until  it  is  "ripe,"  or  "gamey,"  and  partly  decomposed,  is 
dangerous  to  health. 

Forced  feeding  does  not  seem  to  produce  any  pathological 
conditions  in  the  poultry,  and  even  the  "fatty  liver"  of 
forcibly  confined  and  fed  geese,  in  the  much-priced  delicacy 
"pate  de  foi  gras,"  does  not  seem  to  affect  the  gourmands 
injuriously. 

Live  poultry  is  subject  to  many  and  various  diseases, 
which  render  the  meat  unfit  for  use,  and  the  necessity  of 
rigid  antemortem  inspection  is  apparent  in  this  as  well  as  in 
other  meats. 

Fish  Foods. — A  very  large  variety  of  sea  and  fresh  water 
fishes  are  used  for  food.  Fish  are  allowed  to  die  by  depri- 
vation of  the  oxygen. 

Fish  should  be  used  in  season,  should  be  fresh,  firm,  and 
elastic  to  the  touch.  Fresh  fish  may  be  recognized  by  the 
rigidity  due  to  rigor  mortis,  the  freshness  and  red  color  of 
the  gills,  the  moist,  clear  eye,  and  not  disagreeable  odor. 

Frozen  fish  is  not  palatable,  and  decomposes  very  rapidly 
on  thawing.  There  are  many  cases  of  toxic  and  ptomain 
poisoning  from  eating  stale  fish. 

The  eating  of  certain  shellfish,  crabs,  lobsters,  and  oysters 
is  at  times  fraught  with  danger  to  health,  and  many  cases  of 
wholesale  poisonings  have  been  reported  at  different  times. 

Oysters  are  frequently  purveyors  of  typhoid  fever,  as  they 
have  been  the  cause  of  the  disease,  when  they  are  grown  in 
waters  near  large  towns,  the  waters  of  which  are  very  much 
contaminated  by  sewage  and  typhoid  germs.  The  danger 
of  oysters  is  the  greater  in  that  they  are  very  often  eaten  raw. 

Fish  are  preserved  by  smoking,  drying,  salting,  pickling, 
and  also  canning. 

The  sanitation  of  the  establishments  where  fish  is  prepared 
for  canning  does  not  differ  much  from  the  rules  laid  down  for 
the  sanitation  of  the  manufacture  of  meat  products. 

Other  Foods. — Of  the  other  foods  that  are  most  important 
to  health  are  eggs,  cereals,  nuts,  fruits,  vegetables,  condi- 
ments, and  beverages.     The  public  supply  of  the  foods  may 


POULTRY,  GAME,  FISH  FOODS,  AND  OTHER  FOODS  135 

become  dangerous  to  health  by  reason  of  their  deterioration, 
decomposition,  adulteration,  preservation  with  injurious 
chemicals,  etc. 

Eggs  when  eaten  in  a  state  of  decomposition  are  often  the 
cause  of  gastro-intestinal  disturbances.  Eggs  are  preserved 
by  means  of  cold  storage,  also  by  coating  their  outer  shells 
with  lime  or  some  ingredient  making  the  shell  imper^•ious  to 
air  and  the  entrance  of  microorganisms. 

Cereals  and  nuts  are  used  in  a  raw  state,  also  cooked,  and 
for  the  preparation  of  bread  and  in  the  form  of  gruels,  etc. 

Fruit  and  vegetables  which  largely  consist  of  water,  and 
owe  their  chief  value  to  the  sugar,  acids,  and  aroma,  are 
extensively  used,  and  are  valuable  adjuncts  to  other  foods 
Owing  to  the  perishable  quality  of  most  fruits  and  vegetables, 
their  use  is  limited  to  certain  seasons,  and  much  care  must 
be  taken  during  their  transportation  and  handling.  All 
fruits  and  vegetables  undergo  rapid  decomposition,  and  the 
ingestion  of  such  food  may  become  injurious  to  health. 

Careful  inspection  of  fruit  and  vegetables  is  maintained  by 
all  progressive  municipalities,  in  order  to  prevent  the  sale  of 
partly  decomposed  stock. 

Fruit  and  vegetables,  being  largely  eaten  in  a  raw  state, 
may  act  as  vehicles  of  transmission  of  disease  germs  through 
contact  with  infected  persons.  The  preliminary  washing, 
the  prohibition  of  exposure  to  dust  and  dirt,  and  boiling,  are 
the  best  preventive  measures  against  infection. 

Fruits  and  many  vegetables  are  preserved  by  drying,  by 
means  of  condiments,  by  boiling  and  canning,  also  by  chemical 
preservatives,  which  latter  is,  and  should  be,  prohibited. 

Condiments  are  used  as  relishes  and  in  the  preparation  of 
other  foods.     They  are  largely  adulterated. 

Oils,  sugars,  and  various  beverages  are  used  extensively, 
but  cannot  be  discussed  here. 


136  ■  FOOD  SUPPLY 

QUESTIONS.  l 

What  is  food? 

"^Tiat  are  the  sources  of  human  food? 
"\Miat  is  the  chemical  composition  of  food? 
What  is  a  calorie? 

How  is  the  caloric  value  of  foods  estimated? 
"miat  are  the  dangers  to  health  of  ingestion  of  meat  foods? 
What  parasitic  diseases  may  infect  meat  ? 
TMiat  pathogenic  bacteria  may  infect  meat  ? 
"^Tiat  are  toxins  and  ptomains  and  their  relation  to  meat? 
Xame  the  various  causes  of  unfitness  of  meat  for  food. 
"^^Iiat  are  the  conditions  of  animals  rendering  their  meat  unfit? 
TMiat  are  the  postmortem  changes  affecting  meat? 
How  are  meat  foods  adulterated? 

What  are  the  general  means  of  prophylaxis  of  meat  foods? 
State  the  sanitary'  requirements  for  care  of  the  health  of  food  animals. 
State  the  essential  featiires  of  the  sanitation  of  meat-packing  houses  and 
meat-food  factories. 

Give  essential  points  of  antemortem  meat  inspection. 

Give  essential  points  of  postmortem  meat  iiLspection. 

T\Tiat  are  the  characteristics  of  good  meat  ? 

"V\'hat  are  the  methods  of  meat  preservation? 

What  are  the  advantages  of  each  and  the  objections  to  each? 

T^Tiat  chemicals  are  used  in  meat  preservation? 

TMiat  are  the  objections  to  chemicals  as  means  of  preservation? 

State  the  methods  of  meat  preser\'ation  by  "canning." 

^Tiat  are  the  essential  points  of  a  sanitarj'  super^'ision  of  meat  foods? 

TSTiat  diseases  are  poultrj-  liable  to  suffer  from? 

"UTiat  are  the  characteristics  of  good  poultrj'  meat? 

T\Tiat  are  the  characteristics  of  good  fish? 

State  the  essential  points  of  sanitarj'  super^-ision  of  other  foodsi 


CHAPTER  VII. 

MILK  SUPPLY. 

I.    MILK  SUPPLY  AND  PUBLIC  HEALTH. 

Milk  is  a  universal  food.  It  is  the  sole  food  of  millions  of 
infants  under  one  year  of  age,  the  main  food  of  children 
during  their  first  years  of  life,  and  an  important  adjunct 
food  in  the  diet  of  all  persons  of  all  ages  and  conditions. 

According  to  the  United  States  census  there  were  consumed 
by  the  people  of  the  United  States  (except  the  farming  and 
dairy  producing  population)  not  less  than  740,000,000  gallons 
of  milk,  or  about  23  gallons  per  capita  (1900). 

A  pure  milk  supply  is  therefore  of  paramount  importance 
to  public  health,  not  only  because  milk  is  a  universal  food, 
but  also  because  milk,  being  an  animal  secretion  and  a  most 
favorable  medium  for  bacterial  growth,  is  very  seldom  pure, 
and  is  capable  of  causing  and  transmitting  disease. 

The  effects  of  an  impure  public  milk  supply  are  noticed 
on  the  rate  of  infant  mortality  and  upon  the  general  mor- 
bidity and  mortality  from  certain  causes. 

Milk  and  Infant  Mortality. — Infant  mortality  is  very  much 
greater  than  general  mortality.  The  greatest  causes  of  infant 
mortality  are  the  gastro-intestinal  diseases.  Gastro-intestinal 
diseases  are  chiefly  due  to  impure  food.  Milk  being  the  chief 
food  of  infants,  infant  mortality  is  chiefly  due  to  impure  milk. 

The  following  statistical  data  as  to  the  foregoing  logical 
conclusions  are  proof  of  the  relation  of  milk  to  infant  mortality  r 

1.  The  Enormous  Infant  Mortality. — In  England  (1905)  the 
general  death  rate  was  15.2  per  1000.  The  death  rate  of 
infants  was  128  in  rural,  and  183.8  to  198.3  in  cities,  per  1000 
births. 

>  The  statistical  data  are  taken  from  Bulletin  No.  41,  Milk  and  its  Rela- 
tion to  Public  Health. 

(137) 


138  MILK  SUPPLY 

In  Germany,  of  1000  children  born  alive,  235  die  during  the 
first  year. 

In  France,  the  death  rate  of  infants  under  one  year  was, 
during  1892  to  1897,  per  1000  deaths  of  all  ages,  145.35 
(in  Paris),  and  184.73  in  other  large  cities. 

In  the  United  States,  out  of  545,533  deaths  in  the  regis- 
tration area  during  1905,  there  were  105,533  deaths  among 
infants  under  one  year. 

The  greatest  infant  mortality  is  in  Russia  (268  per  1000 
births  during  1892  to  1901);  the  lowest  infant  mortality  is  in 
Norway  (90  per  1000). 

2.  Gastro-intestinal  Diseases  as  Causes  of  Infant  Mortality. — 
Out  of  the  105,553  infantile  deaths  in  the  United  States  dur- 
ing 1905,  39,399  died  from  diarrhea  and  enteritis. 

In  Paris  and  in  other  cities  of  France  having  a  population 
of  over  30,000,  the  deaths  from  diarrhea  per  1000  infants 
dying  from  all  causes,  was  from  212.8,  in  January,  to  606.4 
in  August. 

Other  data  show  the  same  large  proportions  of  infants' 
death  due  to  gastro-intestinal  diseases,  and  the  increase  of  the 
rate  during  the  hot  summer  months. 

3.  Breast  Feeding  and  Pure  Milk  Lessen  Infant  Mortality. — 
According  to  Newsholme,  the  number  of  deaths  from  epidemic 
diarrhea  of  infants  under  one  year  of  age  is  not  much  more 
than  one-tenth  among  breast-fed  babies  as  compared  with 
artificially  fed  babies. 

The  death  rate  in  the  New  York  Infant  Hospital  in  1902 
was  7.47  per  cent,  among  breast-fed  babies,  while  among 
bottle-fed  babies  it  was  62.14  per  cent. 

In  1891  the  death  rate  among  New  York's  children  under 
five  years  was  96.2  per  1000,  and  136.4  during  the  summer 
months;  while  after  the  increase  in  the  consumption  of 
Strauss'  pasteurized  milk,  the  death  rate  of  1906  was  but  55 
per  1000,  and  but  62.7  during  the  summer  months. 

Milk  and  Disease.— The  intimate  relation  of  milk  with  cer- 
tain diseases  has  been  claimed  by  many  sanitarians  and 
proved  in  many  instances. 


MILK  SUPPLY  AND  PUBLIC  HEALTH  139 

Tuberculosis  from  Milk. — Despite  the  fact  that  bovine  tu- 
berculosis is  not  identical  with  human  tuberculosis,  and  that 
primary  intestinal  tuberculosis  is  very  rare,  Koch's  asser- 
tion that  cow's  milk  does  not  cause  human  tuberculosis  is 
vigorously  combated  by  most  investigators.  The  compara- 
tively greater  frequency  of  tuberculosis  among  children  has 
been  cited  as  a  strong  argument,  among  others,  for  the 
causative  relation  between  milk  and  tuberculosis.  The  tu- 
bercle bacilli,  so  often  found  in  milk  (according  to  Hess,  16 
per  cent,  of  New  York  City  milk  is  tuberculous),  are  certainly 
not  without  effect  on  the  persons  consuming  such  milk,  espe- 
cially when  such  persons  are  weak,  young,  and  suffer  from 
some  gastro-intestinal  diseases  denuding  the  mucous  surface 
of  the  intestinal  tract. 

The  transmission  of  the  germs  of  other  diseases,  such  as 
typhoid  fever,  scarlet  fever,  diphtheria,  and  measles  in  milk, 
have  been  proved  beyond  doubt  in  the  many  epidemics  of 
those  diseases  which  were  shown  directly  due  to  infected  milk. 

The  pathogenic  germs  of  typhoid  fever  have  often  been 
found  in  milk,  where  they  rapidly  develop  and  multiply. 
This  germ  may  also  be  found  and  transmitted  through 
various  milk  products,  like  ice-cream,  cheese,  buttermilk,  etc. 

A  large  number  of  violent  epidemics  of  typhoid  fever  have 
been  traced  to  infected  milk. 

The  most  classical  example  of  a  milk-infected  typhoid 
epidemic  occurred  at  Stamford,  Conn.,  during  1895,  when 
97  per  cent,  of  all  the  386  cases  were  traced  to  milk  supplied 
by  one  dealer.  The  source  of  infection  of  the  milk  of  that 
dealer  was  proved  to  be  an, infected  well.  Numerous  reports 
of  scarlet-fever  epidemics  due  to  milk  infection  have  been 
reported  from  time  to  time,  a  typical  case  being  that  of 
Norwalk,  Conn.,  in  1897.  Besides  the  foregoing  diseases, 
it  has  also  been  found  that  foot-and-mouth-disease,  "milk 
sickness,"  Malta  fever,  cholera,  etc.,  are  traceable  to  milk. 

Besides  causing  certain  infectious  diseases  by  the  germs  of 
pathogenic  bacteria  which  it  may  contain,  milk  is  also  capable 
of  causing  certain  gastro-intestinal  disturbances,  which  often 
result  fatally,  especially  in  infants.     These  are  due  either  to 


140  MILK  SUPPLY 

various  acid  and  other  bacilli  which  may  develop  in  the  milk 
during  and  between  the  time  of  milking  and  consumption, 
or  the  diseases  may  be  due  to  certain  toxins  produced  in  de- 
teriorated milk,  and  the  action  of  which  is  not  always  evident. 

Even  slightly  soured  milk  may  cause  diarrhea  in  young 
infants,  while  milk  which  is  impure  has  been  known  to  cause 
violent  colic  and  intestinal  inflammation. 

Sources  of  Contamination  of  Milk. — The  sources  of  bacterial 
contamination  of  milk  are  very  many,  and  may  be  classified  as 
follows:  (1)  The  milk  animal;  (2)  the  dairy  farm;  (3)  the  water; 
(4)  individuals  handling  the  milk;  and  (5)  milk  utensils. 

The  Milk  Animal. — The  quality  of  the  milk  depends  greatly 
on  the  condition  of  health  of  the  milk  animal. 

The  better  the  health,  the  housing,  the  feeding,  and  the 
care  of  the  animal  the  purer  will  be  its  secretion — milk. 

The  diseases  of  cows  which  may  render  their  milk  unfit 
for  food  are  many,  the  most  important  being  anthrax,  tuber- 
culosis, foot-and-mouth-disease,  malignant  edema,  cattle 
plague,  actinomycosis,  trembles,  septic  diseases,  and  local 
diseases  of  the  udder  and  nearby  organs. 

The  lack  of  cleanliness  of  any  cow,  especially  of  the  udder, 
teats,  tail,  and  under  parts  of  the  body,  are  important  factors 
in  the  cleanliness  of  the  milk  derived  from  that  animal. 

The  Dairy  Farm,  etc. — In  its  peregrinations  between  the 
producer  and  consumer  milk  goes  through  many  places,  in 
each  of  which  there  are  many  chances  and  sources  of  con- 
tamination. 

The  farm  plac€,  the  stable,  the  milk  house,  the  dairy,  the 
creamery,  the  car,  the  bottling  establishment,  the  wagon,  the 
grocery  store,  are  all  places  where  the  milk  may  be  infected 
from  one  or  another  source.  In  all  and  each  of  these  places 
there  are  persons,  utensils,  etc.,  upon  which  germs  of  typhoid 
and  scarlet  fever,  diphtheria,  and  other  infectious  diseases 
may  lurk,  and  which  may  find  lodgement  in  the  milk,  and 
thus  be  carried  to  the  consumers. 

Individual  Milk  Handlers. — A  large  number  of  different  in- 
dividuals handle  the  milk  from  the  time  it  is  derived  from  the 
cow  to  the  time  it  is  consumed. 


THE  CHEMISTRY  AND  PHYSIOLOGY  OF  MILK     141 

The  farmers,  the  milkers,  the  drivers,  the  creamery  workers, 
the  bottlers,  the  milk  dealers,  and  grocery  men  are  some  of  the 
principal  infection  agents  from  whom  the  milk  may  derive 
some  of  the  pathogenic  germs  with  which  it  is  often  contam- 
inated. 

Milk  Utensils. — Another  factor  in  the  source  of  milk  con- 
tamination are  the  various  milk  utensils — the  milk  pail,  the 
strainer,  the  can,  the  bottles,  dippers,  etc. — all  of  which  may 
be  dirty  and  infected  by.  the  persons  handling  them,  and 
other  means. 

,  Water. — Finally,  a  very  important  source  of  contamination 
is  found  in  the  water  supply  of  farms  and  dairies,  of  the  water 
with  which  the  teats  and  udders,  the  cans,  pails,  dippers, 
etc.,  are  washed,  and  of  the  water  which  is  sometimes  inten- 
tionally, and  at  times  unintentionally,  allowed  to  gain  access 
to  the  milk. 

II.   THE  CHEMISTRY  AND  PHYSIOLOGY  OF  MILK. 

Composition. — Milk  is  an  animal  secretion,  and  consists  of 
water,  in  which  are  dissolved  and  suspended  various  solids, 
the  relative  amounts  of  which  depend  on  many  various  factors. 

The  average  composition  of  cow's  milk  is  87  per  cent,  water 
and  13  per  cent,  of  solids. 

The  solids  consist  of:  milk  fat,  3.6  per  cent.;  casein,  3.3 
per  cent.;  albumin,  0.7  per  cent.;  milk  sugar,  4.7  per  cent.; 
mineral  matter,  0.7  per  cent.  Milk  also  contains  oxygen, 
nitrogen,  carbon  dioxide,  a  certain  number  of  enzymes  and 
ferments,  and  numerous  bacteria. 

Milk  fat  is  formed  of  the  glycerides  of  a  number  of  fatty 
acids,  oleic  acid  forming  about  50  per  cent,  of  the  whole. 
The  fat  is  in  the  form  of  globules,  more  or  less  minute,  dis- 
tributed through  the  milk,  and  has  a  tendency,  owing  to  its 
specific  gravity  being  lighter  than  that  of  the  rest  of  the  fluids, 
to  rise  to  the  top,  forming  what  is  called  "cream." 

Cream  is  not  all  fat,  nor  is  it  all  the  fat  contained  in  the 
milk,  but  simply  the  upper  layer  of  the  milk  containing  a 
comparatively  larger  percentage  of  milk  fat. 


142  MILK  SUPPLY 

The  sugar  of  milk  is  lactose.  It  is  less  sweet  than  grape 
sugar,  and  is  converted  in  the  presence  of  lactic  ferments  into 
lactic  acid. 

The  proteid  matter  of  milk  is  largely  casein,  and  but  a  small 
percentage  of  albumin. 

The  minerals  of  milk  are  salts  of  sodium,  calcium,  potas- 
sium, chlorides,  iron,  etc. 

The  composition  of  milk  is  not  always  the  same,  and  there 
are  a  number  of  physiological  and  pathological  conditions 
which  alter  the  composition  of  milk  to  a  greater  or  lesser 
degree. 

Foremilk  is  the  first  four  or  five  streams  of  milk  derived 
during  the  milking;  it  is  very  poor  in  fat  and  very  rich  in 
bacteria. 

Strippings  is  the  last  part  of  milking;  it  is  very  rich  in  fats. 

Skim  milk  is  milk  from  which  part  or  all  the  cream  has 
been  removed. 

Cream  is  the  top  layer  of  the  milk  separated  by  gravity  or  by 
aid  of  centrifuge. 

Colostrum  is  milk  derived  from  cows  about  a  week  before 
and  five  days  after  parturition. 

Condensed  or  evaporated  milk  is  milk  from  which  a  consider- 
able portion  of  water  has  been  evaporated. 

Buttermilk  is  the  product  that  remains  after  butter  is  re- 
moved from  milk  and  cream  in  the  process  of  churning. 

Whey  is  the  product  remaining  after  the  removal  of  fat  and 
casein  from  milk  in  the  process  of  cheese-making. 

Koumyss  is  the  product  made  by  the  alcoholic  fermentation 
of  mare's  or  cow's  milk. 

Butter  is  the  product  made  by  gathering  in  any  manner  the 
fat  of  fresh  or  ripened  milk  or  cream  into  a  mass,  which  also 
contains  a  small  portion  of  the  other  constituents  of  milk, 
and  contains  not  less  than  82.5  per  cent,  of  milk  fat. 

Cheese  is  the  sound,  solid,  and  ripened  product  made  from 
milk  or  cream  by  coagulating  the  casein  thereof  with  rennet  or 
lactic  acid,  with  or  without  the  addition  of  ripening  ferments 
and  seasoning,  and  contains  not  less  than  50  per  cent,  of  milk 
fat. 


THE  CHEMISTRY  AND  PHYSIOLOGY  OF  MILK     143 

Physical  Characteristics  of  Milk. — Normal  milk  has  a  white 
or  slightly  yellowish  color,  is  opaque,  of  sweetish  taste,  and 
pleasant  odor. 

Colostrum  differs  from  normal  milk  in  its  containing  more 
of  albumins  than  caseins,  in  its  consequent  coagulability  by 
heat,  in  the  sugar  being  a  dextrose,  and  in  its  containing 
blood  and  colostrum  corpuscles. 

The  reaction  of  milk  is  amphoteric,  {.  e.,  it  is  acid  to  litmus 
and  alkaline  to  turmeric.  After  lactic  acid  fermentation  takes 
place  the  reaction  becomes  acid,  while  during  later  nitrogenous 
decomposition  the  reaction  may  be  distinctly  alkaline. 

The  specific  gravity  of  milk  depends  on  the  amount  of  the 
solids  and  their  character.  Milk  fat  is  of  lighter  specific 
gravity  than  water,  while  the  other  constituents  are  heavier. 
The  specific  gravity  at  60°  F.  is  1029  to  1032.  The  specific 
gravity  is  lowered  by  higher  temperature,  decrease  of  solids, 
increase  of  water,  increase  of  fats,  and  is  higher  on  increase 
of  total  solids,  decrease  of  water  and  fat,  and  lower  temper- 
ature. 

Bacteria  in  Milk. — Milk  even  when  freshly  drawn  contains 
a  large  number  of  microorganisms.  While  most  of  the 
microorganisms  are  due  to  external  sources,  it  has  never 
been  possible  to  obtain  a  milk  which  is  entirely  free  from 
them.  It  is  probable  that  some  bacteria  may  be  found 
within  the  udder,  as  there  were  found  several  growths  of 
bacteria  even  in  milk  drawn  from  the  udder  through  a  sterile 
cannula. 

Theg  reater  part  if  not  all  of  the  bacteria  in  milk  are  derived 
from  outside  sources,  and  the  greater  the  number  of  persons 
handling  the  greater  the  number  of  changes  from  one  place 
to  another,  and  from  one  vessel  to  another,  and  the  less 
cleanliness  about  cows,  stables,  etc.,  the  greater  the  number 
cf  bacteria  in  the  milk. 

The  number  of  microorganisms  in  the  milk  may  vary  from 
500  in  a  cubic  centimeter  in  a  milk  drawn  under  the  most 
rigid  and  special  aseptic  precautions  to  22,000,000  in  a  cubic 
centimeter  found  in  some  market  milk. 

Ordinary  commercial  milk  contains  a  variable  number  of 


144  MILK  SUPPLY 

bacteria.  The  minimum  for  standard  "certified"  milk  is 
10,000  per  cubic  centimeter,  for  "inspected"  milk  100,000. 
Ordinary  market  milk  may  contain  from  1,000,000  to 
10,000,000  of  bacteria  per  cubic  centimeter,  and,  according 
to  Rosenau,  the  general  milk  supply  of  Washington,  D.  C, 
averaged,  in  the  summer  of  1907,  11,270,000  per  cubic 
centimeter,  and  22,134,000  in  1906. 

The  microorganisms  found  in  milk  embrace  almost  all 
varieties.  Streptococci  and  staphylococci  abound  in  great 
numbers;  the  bacillus  coli  communis  is  a  frequent  guest; 
pathogenic  germs  may  be  often  present,  although  most  of 
the  microorganisms  are  the  non-pathogenic  types. 

Some  of  the  bacteria  present  in  milk  are  capable  of  pro- 
ducing changes  in  its  composition.  Of  these,  the  most  impor- 
tant are  lactic-acid  organisms,  to  which  the  lactic  fermenta- 
tion of  the  milk  is  due;  also  the  organisms  producing  the 
changes  and  fermentations  in  the  casein,  fat,  as  well  as  other 
components  of  the  milk. 

Some  of  the  bacteria  may  produce  certain  toxins  which 
may  cause  gastro-intestinal  inflammations  in  children  or 
adults,  while  the  pathogenic  bacteria  may  cause  the  specific 
diseases  of  which  they  are  the  morbific  agents. 

Changes  in  the  Milk. — As  soon  as  milk  is  drawn  from  the 
cow  certain  physical,  chemical,  and  biological  changes  begin 
to  take  place  within  the  fluid. 

The  physical  changes  are  those  produced  by  the  separation 
of  the  milk  into  an  upper  layer  of  cream  and  a  lower  of  skim 
milk.  Later  on,  further  separation  of  the  solid  part  of  milk 
from  the  fluid,  by  coagulation,  etc.,  may  take  place. 

The  chemicobiological  changes  are  due  to  ferments,  en- 
zymes, and  bacteria. 

Chemical  Changes. — ^The  lactose  of  the  milk  is  split  up  into 
lactic  acid,  alcohols,  etc.  This  causes  the  increasing  acidity 
of  the  milk,  which  acidity  at  first  stops  and  inhibits  other 
fermentations  and  changes,  but  later  may  be  overcome  by 
butyric,  proteid,  and  other  fermentation,  to  which  changes 
in  the  constitution,  odor,  reaction,  etc.,  are  due. 

When  first  drawn,  milk  is  said  to  contain  certain  "germicidal 


PROPHYLAXIS  IN  MILK  SUPPLY  145 

properties,"  which  exert  a  restraining  influence  on  the  multi- 
plication of  bacteria  in  sour  milk.  This  germicidal  property 
is  destroyed  by  heating. 

To  bacterial  activity  are  also  due  the  changes  in  the  color 
or  taste  in  the  inilk.  Thus  at  times  a  red  or  blue  milk,  or 
a  ropy,  slimy  milk,  or  an  intensely  bitter  milk,  is  produced. 

Milk  Adulteration. — Milk  is  adulterated  by  the  addition  of 
water,  by  dilution,  by  subtraction  of  cream  or  skimming,  by 
both  watering  and  skimming,  by  the  addition  of  thickeners, 
coloring,  etc.,  and  by  the  addition  of  artificial  preservatives; 
it  is  also  regarded  as  adulterated  when  it  is  below  a  certain 
chemical  or  bacteriological  standard  which  is  prescribed  by 
a  state  or  municipality. 


III.  PROPHYLAXIS  IN  MILK  SUPPLY. 

The  Sanitary  Production  of  Clean  Milk. — The  best  means  to 
prevent  the  spread  of  disease  and  the  ill  effects  from  impure 
milk  is  a  thorough  system  of  sanitary  production  of  milk  and 
its  sanitary  supervision  from  the  time  it  leaves  the  milked 
animal  to  the  time  it  reaches  the  consumer. 

The  production  of  clean  milk  embraces  the  proper  regula- 
tion of  the  following  major  sanitary  details  in  the  production 
and  marketing: 

The  water  supply  and  drainage  of  the  farm. 

The  surroundings,  barnyard,  and  stabling  of  the  cows. 

The  care  for  the  health  and  the  feeding  of  the  cows. 

Milking,  milkers,  and  care  of  milk. 

The  regulation  of  dairies,  bottling  and  milk  establishments. 

Water  Supply  and  Drainage  of  Dairy  Farms. — The  close  re- 
lations between  drainage,  water  supply,  and  clean  milk  make 
it  imperative  that  provision  is  made  for  the  efficient  and 
sanitary  removal  of  all  waste  matters,  and  also  for  the  supply 
of  pure  uncontaminated  source  of  water  supply. 

Privy  vaults  and  leeching  cesspools  should  not  be  allowed 

at  all  on  dairy  farms,  a  proper  disposal  of  sewage  on  such 

places  being  some  form  of  irrigation,  surface  or  subsurface, 
10 


146  MILK  SUPPLY 

or  earth  closets  and  removal  of  all  fluid  sewage  to  distant 
fields  and  garden. 

Manure  should  not  be  allowed  to  accumulate  in  barnyards 
and  stables,  but  should  be  collected  twice  daily,  pressed  into 
barrels,  or  removed  into  distant  parts  of  the  fields,  upon  which 
it  may  be  spread,  provided  the  drainage  of  such  fields  may  not 
contaminate  sources  of  water  supply. 

No  source  of  water  supply  should  be  situated  within  several 
hundred  yards  from  stables,  barnyards,  privy  vaults,  or  cess- 
pools, nor  anywhere  where  they  may  receive  the  drainage 
from  the  same.  Ponds,  small  surface  collections  of  water, 
rivers  which  are  contaminated  by  sewage  and  surface  drain- 
age, and  shallow  wells  should  not  be  relied  on  for  the  supply 
of  water  for  the  dairy  farm;  and  cisterns,  springs,  and  deep 
wells,  when  used,  should  be  protected  from  contamination 
with  sewage  and  properly  constructed,  covered,  and  cared  for. 

Surroundings,  Barnyard,  and  Stables. — All  places  where  milk 
animals  are  kept  and  all  their  surroundings  should  be  kept 
free  from  manure,  dirt,  refuse,  and  stagnant  pools  of  water, 
nor  should  they  be  situated  near  marshy  or  water-logged 
ground. 

Barnyards  should  be  located  on  elevated  ground,  with 
sloping  sides  to  facilitate  drainage,  and  should  be  used  exclu- 
sively for  the  cows,  no  other  domestic  animals  being  allowed 
within,  nor  should  they  have  accumulations  of  dirt  and  refuse 
or  stagnant  pools  of  water. 

Stables  should  be  specially  constructed  for  the  purpose. 
One-story  buildings  of  brick  or  concrete  are  best;  no  open 
second-story  haylofts  should  be  allowed,  nor  any  cellars  or 
manure  pits  under  the  stables.  When  stables  are  constructed 
several  stories  high,  each  floor  should  be  separated  with 
dust-tight  floors. 

Floors  are  best  to  be  constructed  of  bricks  laid  in  cement 
mortar,  or  of  concrete  with  cement  top,  or  of  tiles — never  of 
dirt  or  wood. 

Walls  and  ceilings  should  be  hard  plastered  on  their  inner 
surfaces  and  whitewashed,  or  painted  with  light-colored  oil 
paint. 


PROPHYLAXIS  IN  MILK  SUPPLY  147 

The  floors  should  be  properly  graded  to  one  point,  where 
they  should  be  drained  into  a  sewer,  if  present,  or  into  a  distant 
cesspool,  properly  cleansed,  emptied  at  certain  intervals,  and 
cleaned  and  disinfected. 

Single  stalls  should  be  of  at  least  the  following  dimensions: 
3^  feet  wide,  7  feet  long,  and  9  feet  high,  and  should  be  pro- 
vided with  iron  stanchions  for  securing  the  cows.  The 
mangers  at  the  head  of  the  stalls  should  best  be  constructed 
of  concrete,  without  nooks  and  corners,  being  thus  easily 
washed  and  cleaned.  At  the  foot  of  all  stalls  there  should  be 
provided  a  gutter,  or  valley  drain,  of  iron  or  concrete,  for 
the  receiving  of  urine,  etc.,  and  such  gutter  should  be  covered 
with  a  removable  perforated  cover,  such  gutters  to  be  graded 
and  drained  into  the  sewer  or  cesspool. 

There  should  be  at  least  600  cubic  feet  of  space  for  each  cow 
in  the  stable,  and  proper  provisions  should  be  made  for  the 
entrance  of  fresh  air  through  lowered  openings  and  windows. 

There  should  be  a  window  or  skylight  for  every  twenty 
feet  or  fraction  thereof  of  the  length  of  the  stable,  and  there 
should  be  at  least  four  square  feet  of  glass  surface  for  each 
cow. 

It  is  best  to  have  in  the  stable  separate  compartments, 
unconnected  with  the  general  stable,  for  cows  that  are  sick 
or  parturient. 

No  water  closets,  privies,  etc.,  should  be  located  within  the 
stables,  nor  should  pigs  or  other  domestic  animals  be  allowed 
within  the  barnyard  or  stable  premises. 

Stable  doors  and  windows  should  be  provided  with  screens 
to  prevent  flies  and  mosquitoes  from  annoying  the  cows. 

The  walls,  floors,  ceilings,  and  all  parts  of  stables  should 
be  cleaned  daily  with  water.  The  stables  should  be  periodic- 
ally emptied,  so  as  to  be  thoroughly  aired,  and  disinfected 
with  solutions  of  lime,  bromine,  or  formaldehyde. 

Care,  Health,  and  Feeding  of  Cows. — No  milk  should  be 
taken  from  cows  that  are  suffering  from  general  diseases, 
from  cows  that  are  greatly  emaciated,  that  are  overdriven, 
overexcited,  or  frightened,  nor  from  cows  that  suffer  from 
some  local  septic  disease  of  the  teats  or  udder. 


148  MILK  SUPPLY 

Special  care  must  be  taken  to  detect  cows  that  are  suffering 
from  tuberculosis,  and  to  exclude  such  cows  from  the  herd. 
Cows  should  be  tested  with  tuberculin  by  competent  veteri- 
narians at  stated  intervals,  and  all  cows  which  react  to  the 
test  be  excluded  and  destroyed. 

Daily  examination  of  the  cows  for  any  abnormalities  and 
signs  of  incipient  disease  should  be  a  routine  procedure  of  the 
caretaker  of  the  animals. 

Cows  must  not  be  abused,  overdriven,  or  allowed  to  be 
pestered  by  flies  or  domestic  animals.  They  must  be  pro- 
tected from  too  glaring  sunshine,  from  rain  and  storm,  must 
be  kept  in  the  pasture,  in  the  fresh  air,  and  exercised  daily. 

Proper  provision  for  a  supply  of  pure  water  must  be  made, 
and  cows  should  be  fed  on  fresh  hay,  grass,  corn,  and  whole 
grains,  but  no  ill-smelling  fermented  vegetables,  worm-eaten 
fruit,  strong-smelling  vegetables,  weeds,  brewery  swills,  marsh 
grass,  sour  ensilage,  nor  any  foul  food  should  be  given  to 
cows.     Salt  should  be  accessible  at  all  times. 

Cows  should  be  cleaned,  brushed,  and  groomed  daily,  and 
the  under  surface  of  body,  the  abdomen,  and  flanks  should 
be  washed  with  warm  water  immediately  before  milking  and 
wiped  with  a  damp  cloth.  The  hair  on  the  tail  and  around 
the  udder  should  be  clipped  short. 

The  air  of  stables  at  milking  time  should  be  free  from  dust 
or  offensive  odors,  and  no  sweeping  or  disturbing  the  manure 
should  be  done  immediately  before  or  during  milking. 

Milkers,  Milking,  and  the  Care  of  Milk. — Milkers  shall  be 
free  from  general  and  local  diseases,  shall  pare  their  nails, 
scrub  their  hands,  and  wash  them  before  milking,  and  shall 
don  special  clothes,  caps,  overalls,  which  shall  be  white  and 
clean,  and  not  be  used  for  any  other  purpose  or  at  any  other 
time. 

The  milking  shall  be  done  with  dry  hands,  evenly,  quiedy, 
gently,  cleanly,  and  thoroughly,  and  about  the  same  time  and 
by  the  same  persons  every  day. 

Discard  the  first  few  streams  of  milk — the  foremilk — ■ 
which  is  very  poor  in  fat  and  contains  very  many  germs;  also 
reject  any  milk  which  looks  abnormal  in  color  or  consistency. 


PROPHYLAXIS  IN  MILK  SUPPLY  149 

If  part  of  the  milk  is  accidentally  contaminated  with  dirt 
or  flies,  etc.,  reject  that  part  of  the  milk,  and  do  not  mix  it 
with  the  rest  of  the  milk. 

Narrow-mouthed,  partly  covered  pails  are  preferred  for 
milking,  and  sterilized  gauze  or  cotton  should  be  put  over 
the  metal  strainers. 

Pails  and  other  utensils  should  be  rinsed  in  warm  water, 
scrubbed  with  an  alkaline  solution  and  water,  scalded  with 
hot  water,  and  boiled  or  sterilized  in  a  steam  sterilizer. 

No  loud  talking,  sneezing,  coughing,  tobacco  spitting,  or 
general  expectoration  should  be  allowed  during  milking. 

The  straining  and  cooling  of  the  milk  after  milking  must  not 
be  done  in  the  stable.  Separate  independent  milk  houses, 
specially  constructed  for  the  purpose,  separate  from  any 
other  building  or  the  living  house,  should  be  provided  for 
the  handling  and  keeping  of  the  milk  from  the  time  it  is 
taken  from  the  stable  to  the  time  of  its  removal  to  market, 
such  milk  houses  to  be  free  from  any  domestic  animals, 
clean,  without  dust  and  dirt,  the  inner  surfaces  of  walls  and 
ceilings  clean  and  whitewashed,  the  floor  hard  and  cleansible, 
and  provided  with  plenty  of  natural  light  and  windows  for 
ventilation. 

The  straining  of  the  milk  must  be  done  carefully  and  asep- 
tically,  and  any  machinery  used  for  aeration  or  cooling  be 
kept  clean  and  in  sanitary  condition. 

When  the  milk  is  cooled  by  immersion  in  tubs  of  running 
water,  care  must  be  taken  that  no  water  gain  access  to  the  milk. 

The  temperature  of  milk  must  be  rapidly  reduced  to  45°  F. 

Regulation  of  Dairies,  Bottling  Establishments,  and  Stores. — 
Dairies  and  creameries  must  be  well  lighted  and  ventilated, 
the  inner  surfaces  of  walls  be  clean,  whitewashed,  or  painted 
with  light-colored  oil  paint,  so  that  they  may  be  washed  with 
hot  water.  The  floors  are  best  made  of  concrete,  tiles  or 
stone  laid  in  cement  mortar,  and  the  establishments  used  for 
no  other  purpose  except  the  handling  of  milk  and  its  products. 

No  bottling  should  be  done  anywhere  except  in  establish- 
ments specially  fitted  for  the  purpose. 

Bottling  machines  should  be  made  entirely  of  metal,  with 


150  MILK  SUPPLY 

no  rubber  about  them,  and  should  be  sterilized  in  a  closed 
steam  sterilizer  before  every  bottling. 

Milk  cans  should  be  of  metal,  or  glass,  with  smooth  joints, 
without  seams,  nooks,  or  corners;  bottles  should  be  of  the 
variety  called  "common  sense,"  and  be  capped  with  sterilized 
paraffined  paper  disks. 

Cans,  bottles,  and  all  other  milk  utensils  should  be  cleaned 
by  first  being  thoroughly  rinsed  in  warm  water,  then  washed 
and  scrubbed  with  a  stiff  brush  and  soap,  or  other  alkaline 
solution,  and  hot  water,  and  after  that,  being  sterilized  by 
boiling  or  in  steam  sterilizers,  after  which  they  must  be  dried 
and  kept  inverted  in  free  air  and  clean  places. 

Stores  in  which  milk  is  sold  and  handled  should  be  clean, 
their  walls  and  ceilings  whitewashed,  and  floors  well  scrubbed 
and  clean.  The  milk  can  should  be  kept  at  a  distance  from 
foul  and  strong-smelling  vegetables,  and  foods  should  be  kept 
at  the  temperature  of  45°  F.,  and  the  can  covered  at  all  times, 
and  the  milk  should  be  stirred  before  each  sale. 

No  sleeping  should  be  allowed  on  the  premises,  nor  should 
there  be  any  communicating  doors  or  openings  between  the 
store  proper  and  living  rooms,  and  no  children  or  domestic 
animals  be  allowed  in  the  store  or  near  the  milk  vessels. 

The  refrigerator  where  milk  and  its  products  are  kept 
should  be  clean  and  free  from  foul  odors,  and  the  waste  from 
said  refrigerator,  when  not  otherwise  properly  connected, 
should  be  made  to  discharge  into  a  properly  trapped,  sewer- 
connected,  water-supplied  open  sink  in  cellar  or  in  store. 

During  transportation  milk  should  be  kept  refrigerated, 
and  the  temperature  not  over  50°  F.,  and  the  cans  should  be 
full,  well  covered,  and  the  milk  protected  from  too  much, 
agitation  and  churning. 

Cans  and  bottles  should  be  la'belled  with  the  name  of  the 
wholesale  dealers,  as  well  as  with  the  name  of  the  dairy  from 
which  the  milk  is  derived,  with  date  of  milking,  and  if  pas- 
teurized, with  the  date  of  such  procedure. 

Milk  Preservation. — ^The  rapid  changes  produced  in  the 
milk  immediately  after  its  being  derived  from  the  animal, 
changes  due  to  chemical,  fermentative,  and  bacterial  processes 


PROPHYLAXIS  IN  MILK  SUPPLY  151 

in  the  milk,  make  it  incumbent  that  milk  should  be  consumed 
as  soon  after  its  production  as  possible. 

This  is  impossible  in  the  larger  cities,  which  get  their  milk 
supply  from  distant  parts — sometimes  several  hundred  miles 
distant — and  therefore  the  milk  coming  to  the  inhabitants  of 
such  cities  is  at  least  twenty-four  or  forty-eight  hours  old. 

Unless  some  means  of  preservation  are  used,  milk  could  not 
be  kept  for  so  long  a  period  without  deterioration. 

The  simplest  and  cheapest  method  of  preservation  is  by 
means  of  low  temperature. 

Cold  does  not  kill  bacteria,  nor  does  it  destroy  the  infective 
quality  of  pathogenic  bacteria ;  it  is,  however,  one  of  the  best 
means  of  inhibiting  the  action  of  bacteria,  retarding  their 
development,  preventing  the  milk  from  rapidly  becoming 
soured  and  from  undergoing  fermentative  changes. 

Cold  does  not  change  the  digestibility  nor  the  character 
of  the  milk  and  its  constituents,  and  a  clean  milk,  not  con- 
taining too  many  bacteria,  will  keep  sweet  and  wholesome  for 
a  day  or  more  at  a  temperature  of  under  50°  F. 

Boiling  the  milk  for  a  short  time  kills  a  number  of  bacteria, 
but  does  not  destroy  all  the  spore-bearing  organisms,  and  a 
complete  sterilization,  i.  e.,  destruction  of  all  spore-bearing 
bacteria,  toxins,  and  ferments,  may  be  accomplished  only  by 
subjecting  the  milk  to  a  temperature  of  248°  F.  for  at  least 
two  hours. 

Spore-bearing  bacteria  are  not  often  found  contaminating 
the  milk,  and  boiling  for  fifteen  to  thirty  minutes  is  ordi- 
narily a  safe  procedure,  and  may  furnish  a  sterile  milk. 

Boiling  and  sterilization  of  milk,  however,  produce  certain 
changes  in  the  milk  which  make  it  less  digestible  and  unde- 
sirable, especially  as  an  infant  food. 

The  changes  produced  are  caramelization  of  the  lactose, 
partial  coagulation  of  the  serum  albumins,  destruction  of  all 
ferments,  expulsion  of  carbon  dioxide  and  other  gases,  certain 
changes  in  the  mineral  constituents,  altering  of  appearance 
and  taste,  and  rendering  it  less  digestible. 

Pasteurization  of  Milk. — By  pasteurization  of  milk  is  under- 
stood a  process  of  heating  the  milk  at  a  temperature  and  for 


152  MILK  SUPPLY 

a  time  sufficient  to  destroy  the  most  common  pathogenic 
germs,  without  at  the  same  time  destroying  the  ordinary 
milk  ferments,  nor  altering  its  taste,  appearance,  and  digesti- 
bility. 

According  to  Rosenau,  the  best  temperature  and  length  of 
time  for  efficient  pasteurization  is  heating  the  milk  for  twenty 
minutes  at  a  temperature  of  60°  C.  (140°  F.). 

This  temperature  and  length  of  time  do  not  destroy  the  fer- 
ments and  do  not  alter  the  milk,  but  absolutely  destroy  all 
known  pathogenic  germs,  such  as  those  of  tuberculosis,  ty- 
phoid, cholera,  dysentery,  diphtheria,  tetanus,  etc.,  excepting 
only  the  spore-bearing  organisms.  Pasteurized  milk  must 
be  rapidly  cooled  immediately  after  heating. 

Advantages  of  Pasteurization  of  Milk. — (1)  That  most  if  not 
all  of  the  common  bacteria  and  their  toxins  are  killed.  (2) 
That  the  ordinary  ferments  and  germicidal  properties  of  the 
milk  are  not  destroyed.  (3)  That  the  process  may  be  ac- 
complished on  a  large  scale,  and  furnish  a  commercially 
safe  milk.  (4)  That  the  taste,  appearance,  odor,  and  cream- 
separation  quality  of  the  milk  are  not  altered.  (5)  That 
pasteurized  milk,  if  kept  cold,  furnishes  a  clean,  healthy  milk, 
safe  for  infant  food  and  other  uses. 

Disadvantages  of  the  Pasteurization  of  Milk. — The  following 
are  some  of  the  objections  which  are  urged  by  the  opponents 
of  pasteurization  upon  a  large  and  commercial  basis: 

1.  That  the  spore-bearing  bacteria  and  bacterial  toxins  are 
not  destroyed,  and  the  milk  is  therefore  not  wholly  safe. 

2.  That  pasteurization  stops  lactic-acid  fermentation,  and 
thus  destroys  the  only  "nature's  danger  signal,"  and  the  first 
symptom  by  which  aged  milk  is  known. 

3.  That  unless  pasteurized  milk  is  rapidly  cooled  and  kept 
under  50°  F.,  certain  fermentative  changes  which  are  ordi- 
narily stopped  by  lactic-acid  fermentation  increase  in  activity, 
owing  to  the  destruction  of  lactic-acid  bacilli  by  the  pasteuri- 
zation. 

4.  That  pasteurization,  by  presennng  unclean  milk  for 
some  time,  may  induce  the  producers  to  furnish  dirty  milk, 
discourage   rigid   cleanliness,  and   promote   carelessness  on 


PROPHYLAXIS  IN  MILK  SUPPLY  153 

the  part  of  the  producer  who  relies  entirely  on  the  pasteuriza- 
tion to  preserve  the  milk. 

5.  That  pasteurization  furnishes  a  "purified"  milk  instead 
of  a  "pure"  milk. 

However,  similar  objections  may  be  urged  against  filtration 
of  drinking  water,  and,  much  as  it  is  desirable  to  obtain  a 
perfectly  clean  milk  within  a  few  hours  after  milking,  this  is  as 
yet  impossible  for  large  cities,  and  pasteurization  on  a  large 
scale,  provided  it  is  done  under  sanitary  supervision,  is  still 
the  best  method  of  preservation.  It  is  to  be  insisted  upon, 
however,  in  commercial  pasteurization,  that  the  milk  bottles, 
etc.,  should  be  plainly  labelled  with  degree,  time  of  heating, 
and  time  of  drawing  of  the  milk. 

The  objections  to  the  chemical  artificial  preservation  of 
milk  by  formaldehyde,  borax,  and  boracic  acid  are  the  same 
as  those  enumerated  in  the  section  on  artificial  preservation 
of  meat  and  other  foods.     It  is  entirely  prohibited. 

Sanitary  Supervision  of  Milk.^ — A  complete  system  of  sanitary 
supervision  of  milk  must  embrace  the  following  measures: 

1.  State  inspection  and  tests  of  cattle  dairy. 

2.  Inspection  of  drainage  and  water  supply  of  dairy  farms. 

3.  Periodical  inspection  of  dairy  construction,  equipment, 
etc. 

4.  State  or  municipal  licensing  of  all  establishments  and 
persons  producing,  manufacturing,  transporting,  or  selling 
milk. 

5.  Periodical  inspection  of  farms,  creameries,  factories, 
stores. 

6.  Formulation  of  official  standards  of  milk  and  milk 
products. 

7.  Formulation  of  bacterial  standards  for  milk. 

8.  Collection  of  samples  and  chemical  and  bacteriological 
examination. 

9.  Labelling  of  all  milk  sold,  with  the  time  of  production, 
place,  owner,  roads  and  means  of  transportation,  and  names 
of  wholesale  dealer,  etc.,  so  as  to  fix  responsibility. 

10.  Commercial  pasteurization  on  a  large  scale  under  sani- 
tary supervision  of  municipal  authorities. 


154 


MILK  SUPPLY 


The  foregoing  measures  are  necessary  if  a  pure  milk 
supply  is  to  be  guaranteed  for  the  inhabitants  of  large  cities 
and  for  the  prevention  of  the  ill  effects  of  impure  milk  upon 
public  health. 

Foodstuff  Standards. — A  standard  of  food  is  a  measure  of 
food  quality  established  by  law. 

The  "standards  of  foods  expressed  in  form  of  definitions 
are  so  fixed  that  a  departure  from  the  maximum  or  mini- 
mum prescribed  is  evidence  that  such  article  is  of  inferior 
quality." 

The  following  are  the  U.  S.  standards  for  milk  and  its 
products : 


Solids  not  fat. 

Milk  fat. 

Total  milk  solids 

Milk    .-777 

8.5% 

3.25% 

11.75% 

Skim  milk 

9.25 

Condensed  milk  . 

7.0 

28.00 

Cream 

18.0 

Butter       .       .       . 

82.5 

Cheese 

50.0 

Ice  cream 

14.0 

Fruit  ice  cream  . 

12.0 

IV.  MILK  INSPECTION  AND  TESTING. 


The  methods  of  examining  and  testing  milk  for  the  different 
impurities  it  may  contain,  and  detecting  the  adulterations  to 
which  it  is  often  subjected  are  physical,  chemical,  and  bacte- 
riological. By  the  physical  examination  is  determined  the 
appearance,  color,  odor,  and  specific  gravity  of  the  milk, 
together  with  the  variations  from  the  normal.  By  the  chem- 
ical examination  we  may  determine  the  exact  amount  of  solids 
in  the  milk,  also  the  exact  percentage  of  each  solid  in  the  fluid. 
A  bacteriological  examination  will  determine  the  number  of 
bacteria  in  the  milk  and  the  presence  or  absence  of  pathogenic 
bacteria  in  the  same. 

The  precautions  in  the  examination  of  milk  to  be  taken  are: 
(1)  That  the  milk  must  be  thoroughly  mixed;  (2)  that  it  should 
not  be  partly  frozen;  (3)  that  the  milk  to  be  tested  should  not 
be  partly  churned,  or  partly  separated  of  its  cream;  and  also 
(4)  that  it  should  not  be  partly  or  wholly  coagulated. 


MILK  INSPECTION  AND  TESTING  155 

In  order  to  make  proper  tests,  we  must  take  fair  samples  of 
the  milk  from  a  given  quantity  of  the  marketed  milk,  and 
precautions  must  be  observed  in  the  manner  of  taking 
samples,  so  as  to  get  a  fair  and  just  sample  of  the  whole 
quantity  of  milk  to  be  tested,  instead  of  but  a  small  part  of 
the  fluid. 

A  thorough  mixing  of  the  milk  is  necessary  in  order  to  give 
it  uniformity,  and  in  order  that  the  sample  of  milk  taken  for 
testing  should  fairly  represent  the  whole  milk  to  be  tested 
instead  of  but  a  part. 

Partly  frozen  milk  will  not  give  a  good  test,  because  the 
frozen  part  represents  the  watery  part  of  the  milk,  so  that  the 
rest  of  the  milk  will  show  a  richer  fluid  and  a  higher  per- 
centage of  solids. 

Milk  which  has  been  partly  churned  and  has  butter  granules 
floating  in  it,  or  milk  from  which  the  cream  has  wholly  or 
partly  been  separated,  will  naturally  not  give  the  normal  per- 
centage of  fat  in  the  fluid,  and  the  sample  of  the  milk  taken 
may  not  be  a  fair  sample  of  the  whole  fluid. 

A  milk  which  has  been  partly  or  wholly  coagulated  will 
not  give  a  fair  sample  for  testing  because  of  the  separation 
of  the  whey  and  solids. 

Milk  which  is  partly  frozen  must  be  thawed,  so  that  the 
whole  fluid  becomes  uniform;  milk  which  has  been  partly 
churned  and  contains  butter  granules  floating  in  it  must  be 
heated,  so  that  these  granules  melt;  milk  which  has  been 
partly  or  wholly  coagulated  must,  if  a  sample  from  it  must  be 
taken,  treated  with  alkalies  sufiicient  to  dissolve  the  coagu- 
lum;  while  a  milk  which  has  been  partly  separated  of  its 
cream  must  be  thoroughly  mixed  and  made  uniform  before 
the  sample  is  taken. 

In  mixing  milk  care  must  be  taken  not  to  stir  too  violently, 
so  as  not  to  churn  the  milk  or  to  mix  it  with  air;  the  best 
means  of  mixing  milk  and  getting  a  uniform  mixture  is  by 
pouring  from  one  vessel  to  another. 

The  physical  examination  of  milk  is  of  very  great  impor- 
tance, and  may  give  valuable  information  to  the  inspector. 
The  color  of  the  milk,  its  opacity,  its  resistance  to  the  immer- 


156  MILK  SUPPLY 

sion  of  a  lactometer,  its  adherence  to  the  instrument,  the  visi- 
bility of  the  instrument  through  the  glass  test-tube,  are  all 
valuable  indications  in  the  hands  of  an  experienced  inspector. 
A  milk  which  is  bluish  in  color,  which  allows  the  lactometer 
to  sink  with  little  resistance,  which  runs  down  the  instrument 
in  thin  bluish  streaks,  which  hardly  adheres  to  the  instru- 
ment, and  which  is  so  little  opaque  that  the  instrument  is 
readily  seen  through  the  test-tube,  is  a  milk  which  is  poor  in 
solids  and  which  is  probably  either  skimmed  or  watered,  or 
both — skimmed  and  watered. 

Milk  is  often  tested  by  the  cream  gauge,  pioscope,  and  lacto- 
scope.  The  cream  guage  is  simply  a  graduated  glass  test-tube 
in  which  .the  milk  to  be  tested  is  allowed  to  stand  for  twenty- 
four  hours,  after  which  time  the  amount  of  the  cream,  as 
indicated  in  the  yellowish  layer  on  top,  is  read  off.  A  good 
milk  usually  shows  about  14  per  cent,  of  cream.  In  order  to 
facilitate  the  better  separation  of  the  cream,  the  milk  is  mixed 
with  an  equal  amount  of  water  and  the  resulting  layer  of 
cream  is  multiplied  by  two  to  show  the  actual  amount  of 
cream  in  the  milk.  The  milk  in  the  gauge  is  also  to  be  put 
in  a  cold  place,  which  favors  the  separation  of  the  cream. 
This  is  a  crude  test. 

The  pioscope  (Heeren)  is  a  small  ingenious  instrument  to 
test  the  quality  of  milk  by  its  opacity  and  color.  The  instru- 
ment consists  of  a  small  rubber  disk  with  a  small  depression 
in  its  centre,  and  of  a  glass  plate  painted  in  segments  of 
varying  shades  of  colors  representing  the  color  of  cream, 
rich  milk,  normal  milk,  poor  milk,  skimmed  milk,  watered 
milk,  etc.  The  inspector  takes  a  drop  of  the  milk  to  be  tested 
and  places  it  in  the  central  depression  of  the  hard  rubber 
disk,  covers  it  with  the  glass  plate,  and  compares  the  opacity 
and  color  of  the  milk  with  the  various  segments  in  the  circle. 
In  the  hands  of  an  experienced  inspector  this  is  a  fairly  reliable 
test. 

The  lactoscope  (Feser)  also  tests  the  milk  by  its  opacity. 
The  instrument  consists  of  a  graduated  glass  cylinder,  in  the 
centre  of  which,  at  the  bottom,  is  fixed  a  small  white  rod  with 
several  black  lines  on  its  face;  4  c.c.  of  the  milk  to  be  tested 


MILK  INSPECTING  AND   TESTING  157 

are  put  into  the  cylinder,  making  the  black  lines  on  the 
rod  invisible  through  the  opacity  of  the  milk.  The  test 
consists  in  carefully  measuring  the  amount  of  water  needed 
to  be  put  into  the  cylinder  to  render  the  fluid  transparent, 
so  as  to  make  the  black  lines  upon  the  rod  visible.  It  is 
obvious  that  the  poorer  the  milk  is  in  quality  the  less  water 
will  it  be  necessary  to  have  in  the  cylinder  in  order  to  make 
the  mrsture  transparent;  and,  on  the  contrary,  the  richer  the 
milk,  the  more  water  will  it  be  necessary  to  add.  The  instru- 
ment is  graduated  and  shows  the  amount  of  estimated  fat  in 
the  milk  according  to  the  number  of  cubic  centimeters  of 
water  added. 

Specific  Gravity. — The  testing  of  milk  by  its  specific  gravity 
is  the  most  frequently  employed  test,  and  is  very  valuable  in 
conjunction  with  the  general  physical  examination  of  the 
milk. 

The  specific  gravity  of  milk  depends  on  the  solids  in  the 
fluid.  Of  these  solids,  sugar  and  the  proteids  are  heavier 
than  water,  while  the  fat  is  lighter.  The  specific  gravity  of 
average  normal  milk  is  1029,  and  may  vary  in  normal  milk 
between  1029  to  1032,  The  specific  gravitv  is  calculated  at 
60°  F. 

Milk  which  has  been  skimmed,  i.  e.,  from  which  a  part  or  the 
whole  of  the  cream  has  been  separated,  xAW  show  an  increased 
specific  gravity,  because  the  absence  of  the  fatty  portion  will 
make  it  denser  and  heavier.  A  milk  which  is  diluted  with 
water  will  show  a  decreased  specific  gravity  because  it  is 
made  thereby  much  less  dense  and  thinner. 

The  testing  of  milk  with  the  Quevenne  lactometer  is  based 
upon  the  relative  specific  gravity  of  the  milk.  This  lactom- 
eter is  graduated  from  15  to  40,  the  scale  reading  as  in 
ordinary  hygrometers  and  showing  the  corresponding  de- 
gree of  specific  gravity.  A  good  milk  will  read  (at  60°  F.) 
upon  this  lactometer  32,  showing  a  specific  gravity  of  1032, 
an  average  standard  milk  will  read  29,  a  watered  milk  will  read 
less  than  29,  according  to  the  amount  of  water  (0  being 
water),  while  a  skimmed  milk  will  read  more  than  32,  up  to 
40,  according  to  the  amount  of  cream  subtracted. 


158  MILK  SUPPLY 

The   lactometer  of  the   Health  Department  of  New  York, 
extensively  used  in  many  places  in  the  United  States,  is  a 
larger   instrument    and   is   graduated    differently    from   the 
Quevenne  lactometer.      According  to  this  instrument  it  is 
assumed  that  1029  is  the  lowest  permissible  specific  gravity 
of  standard  milk,  and  these  29  degrees,  divided  into  100  sub- 
divisions, from  the  top  figure,  0,  showing  the  reading  of  water 
at  60°  F.,  to  100,  which  will  correspond  to  29  on  the  Quevenne 
instrument,  or  1029  specific  gravity  on  the  ordinary  hygrom- 
eter.   The  lactometer  is  graduated  from  0  to  120.    According 
to  the  Board  of  Health  lactometer  a  poor  normal  milk  will  read 
100,  a  good  rich  milk  will  read  between  100  and  110,  a  skimmed 
milk  will  read  between  110  and  120,  while  a  watered  milk  will 
read  under  100,  the  amount  of  water  added  being  indicated 
in  the  reading,  i.  e.,  10  per  cent,  of  water  being  added  if  the 
lactometer  read  90°,  25  per  cent,  at  75°,  etc.     This  instru- 
ment is  more  convenient  for  use,  as  the  stem  is  longer  and  the 
degrees  may  be  read  more  readily,  and  also  the  exact  amount 
of  probable  addition  of  water  may  be  more  readily  calculated. 
As  the  lactometric  readings  are  calculated  at  60°  F.,  cor- 
rections must  be  made  for  any  difference  in  the  temperature  of 
the  milk  above  or  below  60°  F.     When  the  difference  in  the 
temperature  is  very  great,  it  is  best  to  reduce  or  increase  its 
temperature  to  within  10°  of  60°.     The  correction  for  the 
temperature  is  then  0.1°  of  the  Quevenne  lactometer  for  every 
1°  of  temperature,  and  0.3°  of  the  Board  of  Health  lactom- 
eter for  every  1°  of  temperature  above  or  below  60°;  added 
to  the  reading  when  the  temperature  of  the  milk  is  above 
60°  F.,  and  subtracted  from  the  reading  when  the  temperature 
of  the  milk  is  below  60°  F.     The  usual  rough  correction  for 
the  Board  of  Health  lactometer  is  4  degrees  on  the  lactometer 
for  every  10  degrees  on  the   thermometer,  added  or  sub- 
tracted according  as  it  is  above  or  below  60°  F. 

As  the  specific  gravity  of  milk  is  increased  by  skimming 
and  decreased  by  watering,  some  milk  dealers  first  subtract  a 
certain  amount  of  cream,  thus  increasing  the  specific  gravity 
and  lactometer  reading,  and  then  add  sufficient  water  to  again 
decrease  the  specific  gravity  and  lactometer  reading  to  about 


SANITARY  INSPECTION  OF  PRODUCTION  OF  MILK  159 

normal,  so  as  to  deceive  the  inspector  and  give  an  adulterated 
milk  showing  a  normal  reading  on  the  instruments.  The 
only  recourse  of  the  inspector  is  then  to  compare  the  physical 
appearance  of  the  sample  of  milk  with  normal  milk,  when 
there  will  appear  the  difference  in  the  color,  opacity,  and 
density  of  the  fluid. 

The  chemical  tests  of  milk  consist  in  the  examination  for  the 
exact  percentage  of  solids,  and  for  the  testing  for  the  amounts 
and  percentage  of  each  component  solid.  The  usual  tests 
being  those  of  weighing  and  evaporation  for  the  exact  amount 
of  solids,  and  the  Babcock  test  for  the  determination  of 
amount  of  fat  in  the  milk.  For  the  complete  chemical  and 
bacteriological  tests  of  milk  the  student  is  referred  to  special 
works  on  these  subjects. 

V.  SANITARY  INSPECTION  OF  THE  PRODUCTION  OF 

MILK. 

(Department  of  Dairy  Industry,  New  York  State  College 
of  Agriculture.) 

Dairyman  Date 

Location  Postoffice 

No  cows  in  herd  milking  quarts  milk  cans 

or  bottles 
Milk  sold  to  License  No. 

Report  by  at  milking  time.  Hour 

I.  Health  of  the  Herd  and  its  Protection. 

Do  all  cows  appear  healthy? 

Are  udders  sound  and  free  from  signs  of  disease? 

Are  cows  tuberculin  tested? 

Date  of  last  test.  By  whom? 

Is  stable  well  built  to  protect  from  weather? 

Are  cows  brought  in  during  bad  storms? 

How  many  hours  are  cows  out  daily? 

Width  of  stall  Length 


160  MILK  SUPPLY 

Is  stall  comfortable?        How  are  the  cows  tied? 

Kind  and  quality  of  bedding 

Where  are  cows  kept  when  sick  and  at  calving  time? 

Is  the  stable  well  located  ? 

Number  and  size  of  windows 

Size  of  stable  length  width  height 

How  ventilated? 

Kinds  of  feed  used 

Are  they  of  good  quality  and  proportions  ? 

Source  of  water  for  cows 

Method  of  watering 

11.  Cleanliness  of  Cows  and  Their  Surroundings. 

Are  the  cows  clean?  How  are  they  cleaned? 

Is  the  hair  clipped  about  the  udder? 

Is  the  udder  cleaned  before  milking  ?     How  ?     When  ? 

Is  the  stable  free  from  accumulations  of  cowbebs,  dirt, 
and  dust? 

Is  the  stable  whitewashed? 

Any  other  animals  in  stable  ?         Kind  Number 

Same,  adjacent  rooms  What  openings  between? 

How   far   is  privy   from  stable?  Any   chance   of 

contamination  ? 

How    often    is    manure    removed    from    stable? 

Where  to? 

Is  the  barnyard  free  from  manure,  refuse,  stagnant 
water,  etc.? 

Is  the  pasture  clean  and  free  from  injurious  plants  and 
mud  holes? 

Is  the  stable  provided  with  dust-proof  ceilings  and 
partitions  ? 

Is  feeding  done  before  or  after  milking? 

Is  the  floor  swept  or  dampened  before  milking? 

Is  the  air  free  from  dust  and  odors? 


SANITARY  INSPECTION  OF  PRODUCTION  OF  MILK  161 

III.  Construction  and  Care  of  Utensils. 

Are  all  utensils,  such  as  can  be,  thoroughly  cleaned? 

Method  of  washmg  utensils?  How  sterilized? 

Is  the  water  used  for  washing  pure?  How  do  you 

know? 

What  is  its  source? 

Is  the  source  protected  from  contamination  ?  How? 

How  are  utensils  cared  for  after  cleaning? 

Is  a  small-top  pail  used?  What  style  and  size  of 

opening? 

IV.  Health  of  Employees  and  Manner  of  Milking. 

Any  contagious  diseases  in  family  or  among  employees? 
Are  the  milkers  clean  personally? 
Do  the  milkers  wear  special  clean  overalls? 
How  often  are  these  washed? 
Do  the  milkers  wash  their  hands  before  milking? 
Where?  How? 

Do  the  milkers  have  wet  hands  during  milking? 
Are  the  milkers  careful  not  to  dislodge  hair  and  dirt  from 
the  cow  while  milking? 

Is  the  foremilk  discarded?  Where? 


V.  Handling  of  Milk. 

How  is  the  milk  cooled? 

How  soon  after  milking  is  the  milk  cooled? 

To  what  temperature? 

Is  the  milk  handled  in  a  room  detached  from  stable? 

What  kind  of  floor? 

Is  the  milk  room  used  exclusively  for  milk? 

Is  it  clean  and  free  from  dirt  and  odors? 

At  what  temperature  is  milk  kept  after  cooling? 

How  is  milk  cared  for  during  transportation? 

11 


162 


MILK  SUPPLY 


SCORE  CARD  FOR  THE  PRODUCTION  OF  SANITARY 

MILK. 


Date 

Dairy  of 

P.O. 

I. 

Perfect 

Score 

Health  of  the  herd  and 

Health  and  comfort  of  the  cows 

its  protection. 

and  their  isolation  when  sick  or 

at  calving  time 

45 

Location,  lighting,  and   ventila- 

tion of  the  stable 

35 

Food  and  water 

20 

Total 

100 

II. 

Cleanliness  of  the  cows 

Cows 

30 

and    their    surround- 

Stable 

20 

ings. 

Barnyard  and  pasture 

Stable    air — freedom    from    dust 

20 

and  odors 

30 

Total 

100 

III. 

Construction    and    care 

Construction,  cleaning  and  ster- 

of utensils. 

ilization  of  utensils 
Water  supply  for  cleaning,  loca- 

40 

tion  and  protection  of  its  source 

25 

Care  of  utensils  after  cleaning 

20 

Use  of  small-top  milking  pail 

15 

Total 

100     . 

!^ 

IV. 

Health     of     employees 

Health  of  employees 

45 

and  manner  of  milk- 

Clean overall   suits  and  milking 

ing. 

with  clean  dry  hands 
Quiet  milking,  attention  to  clean- 
liness of  udder  and  discarding 

30 

of  foremilk 

25 

Total 

100 

V. 

Handling  of  milk. 

Prompt  and  efficient  cooling 
Handling    milk    in    a    sanitary 
room    and    holding    it    at    low 

35 

temperature 

35 

Protection  during  transportation 

30 

Total 

100 

- 

Total  all  scores 

500 

QUESTIONS 


163 


If  the  total  of  all  scores  is 
480  or  above 
450  or  above 
400  or  above 
Below  400 


And  each  division  is 
90  or  above 
SO  or  above 
60  or  above 
Below  60 


The  sanitary  conditions  are 
Excellent 
Good 
Medium 
Poor 


The  Sanitary  conditions  of  this  dairy  are 
Scored  by 


Inspector. 


QUESTIONS. 

What  are  the  relations  of  the  milk  supply  to  infant  mortality,  tuberculosis, 
and  typhoid  fever? 

What  are  various  sources  of  milk  contamination? 

State  the  composition  of  milk  and  characteristics  of  each  component. 

Define  the  following  terms :  foremilk,  strippings,  skim  milk,  cream,  colos- 
trum, condensed  milk,  butter,  buttermilk,  cheese,  whey,  koumiss. 

Describe  color,  appearance,  reaction,  and  specific  gravity  of  milk. 

What  are  the  variations  in  the  color,  appearance,  and  taste? 

Describe  the  number  and  role  of  bacteria  in  milk. 

Describe  the  changes  in  milk  in  the  first  twenty-four  hours  after  milking 

How  is  milk  adulterated? 

Describe  the  methods  for  securing  pure  milk. 

Give  rules  governing  the  care  of  milk  cows. 

Give  rules  governing  the  barnyard  stable. 

Give  rules  governing  drainage  and  water  supply  of  dairy  farms. 

Give  rules  governing  milk  houses  and  milking,  utensils  and  milker. 

Give  U.  S.  standards  for  milk,  cream,  skim  milk,  butter,  and  cheese. 

What  are  the  means  of  milk  preservation? 

State  advantages  and  disadvantages  of  each. 

Give  advantages  of  pasteurization  and  objections  to  it. 

State  chemicals  used  for  milk  preservation  and  objections  to  them. 

What  are  the  precautions  to  be  taken  in  mixing  milk? 

How  are  samples  of  milk  to  be  taken  for  testing? 

AATiy  is  partly  frozen,  or  partly  separated,  or  coagulated  milk  not  to 
be  taken  as  samples  for  testing? 

What  is  determined  by  the  physical  and  by  the  chemical  examination? 

What  is  the  cream  gauge,  and  how  is  it  used? 

What  is  the  lactoscope  and  how  is  it  used? 

What  is  the  pioscope,  and  how  is  it  used? 

What  is  the  specific  gravity  of  milk,  and  to  what  is  it  due? 

What  increases  and  decreases  the  specific  gravity  of  milk? 

Describe  the  Quevenne  lactometer  and  method  of  its  use. 

Describe  the  New  York  Board  of  Health  lactometer  and  its  use. 

Give  corrections  for  temperature  variations  on  both  lactometers. 

What  are  the  points  in  the  sanitary  inspection  of  the  production  of  clean 
milk? 

What  is  a  daily  milk  score-card? 


CHAPTER  VIII. 

DISPOSAL  OF  WASTE  MATTER. 

I.  WASTE  MATTER  AND  PUBLIC  HEALTH. 

Kinds  of  Waste  Matter. — In  every  human  settlement  with 
large  numbers  of  persons  present,  there  are  bound  to  be 
accumulations  of  various  waste  matter,  which,  if  not  imme- 
diately and  effectively  disposed  of,  may  become  a  menace  to 
the  health  of  the  community. 

The  waste  matter  is  of  various  kinds,  as  follows: 

1.  Waste  matter  due  to  natural  elements — rain  or  snow. 

2.  Street  refuse. 

3.  House  refuse. 

4.  Industrial  waste. 

5.  Dead  bodies^^human  and  animal, 

6.  Sewage  proper. 

Amount  and  Quality  of  Waste  Matter. — These  vary  with  each 
kind. 

Rain  and  Snow. — ^The  quantity  of  rain  and  snow  falling 
upon  a  given  city  may  be  calculated  by  the  multiplication  of 
the  amount  or  depth  of  the  annual  rainfall,  or  snowfall,  by 
all  the  street  and  root  surfaces  in  the  city.  Rain  and  snow 
are  mixed  with  a  large  amount  of  dirt  gathered  from  the  dust 
in  the  air  and  on  the  roof  and  street  surfaces;  the  exact 
amount  of  such  impurities  is  difficult  to  calculate.  There 
may  be  considerable  organic  matter  and  bacteria  in  the  rain 
and  snow  water.  (Burand-Clay  has  found  in  Paris  storm 
water  127,000  germs  to  the  cubic  centimeter.) 

Street  refuse  consists  of  ashes,  cinders,  dust,  paper,  straw, 
fibrous  matter,  animal  and  vegetable  refuse,  coal,  bones, 
offal,  rags,  bottles,  metals,  crockery,  manure  and  excreta, 
dried  and  wet  sputum  and  expectoration,  and  innumerable 
other  organic  and  inorganic  matter. 
(164) 


WASTE  MATTER  AND  PUBLIC  HEALTH  165 

The  quantity  of  street  refuse  differs  according  to  many 
circumstances  and  factors.  In  New  York  City  it  amounts 
to  nearly  4,000,000  tons  a  year,  or,  approximately,  one  ton  a 
year  for  every  living  human  being. 

The  amount  of  organic  matter  in  the  street  refuse  is  very 
large;  according  to  some  authorities  it  is  from  14  to  22  per 
cent. 

Numerous  investigations  have  been  made  of  the  number  of 
bacteria  in  street  refuse.  Manfredi  found  in  the  street  refuse 
of  Naples  6,668,000,000  of  bacteria  to  one  gram  of  refuse, 
with  an  average  of  716,000,000  per  gram.  Uffelman  found 
in  Rostok  street  refuse  from  2,000,000  to  40,000,000  of  germs 
to  the  gram. 

Among  the  germs  found  in  the  street  refuse  and  proved 
to  be  pathogenic  by  inoculation,  were  the  staphylococcus 
pyogenes  aureus,  streptococcus  pyogenes,  the  bacillus  of 
malignant  edema,  the  tetanus  bacillus,  tubercle  bacillus,  etc. 

House  Refuse. — The  quantity  of  house  refuse  is  very  large. 
House  refuse  consists  of  various  organic  and  inorganic  matter, 
such  as  sweepings,  rubbish,  papers,  garbage  from  kitchen 
and  table,  remnants  of  food,  detritus  from  the  various  activ- 
ities within  the  house,  etc. 

House  refuse  contains  much  organic  matter  of  decompo- 
sition, wet  and  dry  sputum,  expectorations,  etc.,  and,  very 
often,  scales  and  discharges  from  scarlet  fever,  typhoid, 
measles,  and  other  infectious  diseases. 

Industrial  Waste. — A  very  large  amount  of  waste  matter 
comes  from  the  various  industrial  processes — from  laundries, 
slaughter  houses,  stables,  tanning  factories,  and  the  thousands 
of  other  various  industrial  establishments. 

A  large  part  of  industrial  waste  matter  consists  of  organic 
matter,  and  may  undergo  decomposition  and  contain  various 
germs. 

Dead  Bodies. — The  number  of  dead  bodies  of  human  beings 
and  of  animals  differs  according  to  the  population  of  the  city 
and  the  rate  of  mortality. 

The  organic  matter  of  dead  bodies  speedily  undergoes 
decomposition  and  putrefaction,  is  attacked  by  millions  of 


166 


DISPOSAL  OF  WASTE  MATTER 


insects  and  germs,  and  contains  a  large  number  of  pathogenic 
germs,  especially  in  those  who  die  from  infectious  disease. 

Sewage. — By  sewage  is  meant  the  liquid  and  solid  excreta 
from  animals  and  human  beings. 

The  manure  and  excreta  from  horses  is  a  part  of  street 
refuse,  although  a  large  part  of  the  same  is  contained  in  the 
refuse  of  stables,  etc. 

According  to  Frankland,  an  average  human  person  voids 
about  40  ounces  of  liquid  and  3  ounces  of  solid  excreta. 

According  to  Zuruck,  the  yearly  amount  of  sewage  for 
100,000  persons  will  be  3650  tons  of  solid  and  36,000  tons 
of  liquid  excreta. 

The  percentage  of  organic  matter  in  feces  varies  from  21 
to  25. 

The  number  of  microorganisms  in  sewage  varies. 

According  to  Suckdorf,  there  were  found  381,000,000  of 
microorganisms  in  1  gram  of  the  fresh  feces  of  a  person  fed 
on  a  mixed  diet. 

Feces  and  urine  undergo  rapid  putrefactive  changes  on 
exposure  to  the  air,  and  especially  when  mixed. 

According  to  Sedgwick,^  the  average  composition  of  fresh 
sewage  in  Lawrence,  Mass.,  during  the  morning  for  1897 
was  (parts  per  100,000) : 


C3 

Albuminoid  ammonia. 

Chlorine. 

Nitrogen  as 

Oxygen 

con- 
sumed. 

^i 

Total. 

Soluble. 

Insol'ble 

Nitrates 

Nitrites. 

3.19 

1.26 

0.78 

0.48 

13.36 

0.18 

0.0182 

7.59 

Bacteria 
per  cubic 
centi- 
meter. 


4,726,000 


Hygenic  importance   of   waste   matter  depends  upon  the 
following  factors: 

1.  The  commercial  value  of  the  waste  matter. 

2.  Odors  and  efSuvia. 

3.  Bulk  and  appearance. 

4.  Toxins  and  gases. 

5.  Infection  of  soil,  air,  and  water. 


1  Principles  of  Sanitarj^  Science  and  Public  Health. 


WASTE  MATTER  AND  PUBLIC  HEALTH  167 

WTiile  the  commercial  worth  of  the  waste  matter  is  seem- 
ingly an  economic  matter  and  not  a  sanitary  one,  the  fact  of 
the  economic  vahie  of  most  waste  matter  bears  a  direct  relation 
to  its  sanitary  utilization  and  disposal.  The  expense  of  dis- 
posal may  be  much  lessened  if  the  organic  and  other  valuable 
matters  could  be  extracted  and  utilized. 

While  the  odors  and  eflfluvia  of  most  waste  matter,  and  even 
of  decomposing  sewage  matter,  have  not  been  found  capable 
of  directly  causing  disease,  there  is  no  doubt  that  their  un- 
pleasantness and  the  disgust  produced  by  them  may  be 
injurious  to  health,  by  preventing  the  enjoying  of  fresh  air 
and  producing  nausea,  anorexia,  etc. 

The  same  may  be  said  about  the  disagreeable  appearance 
of  most  waste  matter. 

All  decomposing  matter  evolves  gases  and  contains  toxins 
which  may  affect  health.  Sulphur  gases,  ammonia,  sul- 
phuretted hydrogen,  carbon  dioxide,  marsh  gas  and  other 
gases  which  in  concentrated  form  may  become  toxic  are 
produced  by  putrefactive  changes  in  organic  matter.  The 
so-called  "sewer  gas"  is  not  a  gas  at  all,  but  the  air  of  sewers, 
which  may  or  may  not  be  mixed  with  other  gases,  and 
may  or  may  not  become  detrimental  to  health,  according  to 
its  purity.  Sewer  air  was  regarded  formerly  as  capable  of 
causing  certain  diseases. 

The  most  dangerous  elements  and  properties  of  all  waste 
matter,  and  especially  of  sewage,  are  due  to  the  possibility  of 
their  carrying  infection  by  the  pathogenic  germs  which  they 
may  contain. 

The  elements  of  infection  are  discharged  by  diseased  ani- 
mals and  by  man  through  the  skin,  respiratory  and  alimentary 
canals.  Hence  these  discharges  contain  all  the  elements  of 
infection,  and  will  produce  the  infection  when  ingested  or 
brought  into  contact  with  uninfected  human  beings. 

The  sputum,  the  expectoration,  the  skin  scales,  the  dis- 
charges from  the  bowels  may,  and  often  do,  contain  tubercle 
bacilli,  scarlet  fever,  diphtheria,  smallpox,  measles,  tjT)hoid, 
cholera,  and  other  pathogenic  germs',  and  may  thus  transmit 
these  diseases  by  those  waste  matters. 


168  DISPOSAL  OF  WASTE  MATTER 

The  transmission  may  be  accomplished  directly  from  per- 
son to  person,  or  through  the  medium  of  clothing,  or  by  the 
aid  of  insects,  or  by  means  of  the  air,  soil,  and  water. 

The  dust  of  air  may  contain  tubercle  bacilli  and  other 
germs. 

The  soil  does  contain  large  numbers  of  pathogenic  germs,  but 
these  cannot  escape  from  the  soil  unless  by  the  aid  of  water. 

Insects  often  carry  the  germs  of  typhoid,  tuberculosis^  etc., 
from  sewage  and  sputum  to  the  food  of  man. 

Water  is  very  often  contaminated  by  typhoid,  cholera,  and 
other  pathogenic  germs  through  the  sewage  thrown  into  the 
water  or  through  drainage  of  same  through  soil. 

Even  sea  water  may  at  times  become  a  vehicle  of  typhoid 
fever,  as  has  been  proved  by  sea  water  infected  with  sewage 
contaminating  oysters  and  other  edible  fishes.  Thus  in  1908 
in  New  York  City,  113  cases  of  typhoid  fever  were  traced  to 
the  use  of  raw  oysters  infected  with  contaminated  sewage. 


II.  DISPOSAL  OF  WASTE  MATTER. 

Rainwater. — ^The  disposal  of  rainwater  becomes  a  serious 
problem  in  cities  where  the  pavements  and  exposed  surfaces 
are  covered  by  non-absorbent  materials  interfering  with  the 
draining  of  storm  water  into  ground;  nor  is  the  collection  of 
large  stagnant  pools  of  water  desirable  from  a  sanitary  stand- 
point. 

Rainwater  collected  on  roofs,  street  pavements,  etc.,  is  com- 
monly disposed  of  by  the  sewerage  system. 

In  the  combined  system  of  sewerage  the  rainwater  is  dis- 
posed of  through  the  same  pipes  through  which  the  sewage 
passes.  This  system  necessitates  pipes  of  larger  caliber,  in 
order.to  take  care  of  the  occasional  large  quantities  of  storm 
water,  which  water  serves  also  to  give  the  sewer  pipes  a 
thorough  flushing.  On  the  other  hand,  the  large  caliber 
sewer  pipes  of  the  combined  system  cause  a  very  sluggish 
flow  of  sewage  in  them  in  ordinary  times,  with  consequent 
adherence  of  sewage  to  the  sides  and  a  decomposition  of 


DISPOSAL  OF  STREET  REFUSE  169 

sewage  and  creation  of  foul  gases.  The  utilization  of  the 
sewage  is  also  more  difScult  in  the  combined  system  because 
of  the  large  dilution  of  the  sewage  and  the  expense  of  sepa- 
rating the  solid  excreta  from  the  fluid. 

In  the  separate  system  of  sewerage  the  rainwater  is  re- 
moved separately  through  a  distinct  system  of  pipes  taking 
care  of  the  rainwater  only,  and  this  water  may  safely  be 
disposed  of  into  rivers  and  nearby  watercourses  without 
special  danger  of  contamination  with  sewage  matter,  as  in 
the  combined  system.  For  smaller  cities,  with  modern  sew- 
age-treatment plants,  the  separate  system  of  di'ainage  is 
much  more  preferable,  and,  although  it  recjuires  a  double 
system  of  pipes,  etc.,  is  cheaper  in  the  end,  and  less  objec- 
tionable in  many  respects. 

Snow. — The  large  snowfall  during  certain  months  of  the 
winter  and  the  accumulation  of  the  snow  in  the  streets  of 
cities  may  become  a  nuisance  and  detrimental  to  health,  on 
account  of  the  mixing;  of  large  amounts  of  organic  street 
refuse  matter  with  the  snow  and  contamination  with  offensive 
refuse  and  possibly  with  products  of  decomposition  and 
pathogenic  germs. 

The  removal  of  snow  from  city  streets  presents  many  diiB- 
culties  and  gives  great  trouble  to  municipalities.  The  com- 
mon method  of  hiring  men  to  shovel  the  snow  into  piles, 
from  which  it  is  loaded  into  wagons  and  dumped  into  the  sea, 
rivers,  or  outlying  places  near  the  city,  has  many  objection- 
able features,  and  is  very  expensive  and  difficult  to  control. 
There  are  some  patented  devices  which  melt  the  snow  in  the 
streets  and  dispose  of  it  into  sewers,  but  such  machines  are 
as  yet  not  very  efficient. 

Street  Refuse.— An  absolutely  efficient  and  sanitary  system 
of  street  cleaning  and  of  disposal  of  street  refuse  has  as  yet 
not  been  devised,  in  spite  of  the  fact  that  it  is  a  problem  of 
paramount  importance  to  public  health,  and  very  large  sums 
of  money  are  spent  upon  street  cleaning  by  municipalities. 

The  street-cleaning  problem  divides  itself  into  three  parts — 
(1)  The  collection,  (2)  the  transportation,  and  (S)  the  final 
disposal. 


170  DISPOSAL  OF  WASTE  MATTER 

The  collection  of  street  refuse  is  commonly  done  by  street 
sweepers,  using  brooms,  shovels,  and  cans.  There  are  used 
also  machine  sweepers,  which  gather  the  dirt  from  the 
street  for  several  feet  at  a  time  and  leave  it  there  to  be  col- 
lected by  the  street  cleaners.  Most  of  the  hand  as  well  as 
machine  sweeping  is  done  without  preliminary  thorough 
wetting,  with  a  consequent  raising  of  dust  and  scattering  of 
refuse  by  wind,  etc.  The  whole  process  is  extremely  crude 
and  unsanitary'.  When  the  streets  are  sprinkled  it  is  better, 
but  the  sprinkling  is  usually  veiw  perfunctory  and  not  thorough 
enough  to  prevent  the  raising  of  dust,  A  scientific,  efficient, 
objection-free  system  of  collecting  street  refuse  has  not  as  yet 
been  devised,  or,  at  least,  not  introduced. 

The  efficiency  of  the  collection  also  depends  on  the  kind 
and  character  of  street  pavement.  The  time  of  collection  of 
street  refuse  is  important,  and  the  practice  in  some  cities,  which 
collect  and  clean  streets  at  night,  when  the  cleaners  are  undis- 
turbed, and  furnishing  clean  streets  for  the  beginning  of  the 
day,  seems  to  have  many  advantages. 

After  collection,  the  transportation  of  street  refuse  in  wagons, 
etc,  demands  care  and  the  provision  of  well-covered  wagons, 
so  that  the  dirt,  and  dust  be  not  blown  o£f  the  wagons  by  the 
wind,  and  also  that  certain  offensive  sweepings,  manure,  etc, 
should  be  prevented  from  giving  off  their  effiuvia  in  the 
streets. 

The  final  disposal  of  street  refuse  differs  in  various  cities, 
A  large  percentage  of  the  inorganic  and  organic  matter  in 
the  street  refuse  has  an  economic  value  and  may  be  utilized 
for  various  purposes.  Indeed,  in  some  cities  the  scow  trim- 
mers and  contractors  pay  large  sums  for  the  privilege. 
Dumping  the  accumulated  refuse  into  the  sea  and  water- 
courses does  not  seem  to  be  an  efficient  system  of  disposal. 
The  best  mode  would  seem  to  be  the  extraction  from  the 
refuse  of  all  of  its  valuable  ingredients  and  destroying  the 
remainder  in  specially  designed  destructors  or  crematories, 
the  heat  of  which  is  at  the  same  time  utilized  for  some  such 
purpose  as  generating  electric  power,  etc. 

The  disposal  of  house  refuse  is  essentially  a  part  of  the 


\ 

DISPOSAL  OF  DEAD  HUMAN  BODIES  171 

general  problem  of  disposal  of  refuse  in  cities.  A  large  part 
of  the  house  refuse  may  be  destroyed  in  the  house,  and  the 
other  refuse  may  be  utilized  in  many  ways. 

The  separation  and  collection  into  separate  receptacles  of 
the  ashes,  papers,  and  garbage,  which  represent  the  three 
main  kinds  of  house  refuse,  makes  the  utilization  of  the 
refuse  much  easier,  as  the  papers  and  rubbish  may  be 
economically  used  for  various  purposes,  if  not  for  fuel; 
the  ashes  may  be  used  for  filling  in  swamps,  etc.,  while  the 
garbage  and  remnants  of  food  may  be  utilized  in  the  manu- 
facture of  soap,  fertilizers,  etc. 

Trade  Waste. — ^The  disposal  of  the  waste  and  refuse  matter 
which  are  produced  by  industrial  establishments  is  regarded 
by  some  municipalities  as  the  duty  of  the  owners  of  the  in- 
dustries. Industrial  establishments  may  utilize  a  large  part 
of  their  waste  matter,  and  the  remainder  may  be  disposed  of 
by  properly  constructed  destructors.  Municipalities  have  a 
right  to  prohibit  the  disposing  of  trade-waste  into  rivers  and 
watercourses,  unless  such  waste  matter  is  previously  chemi- 
cally treated  and  made  harmless. 

The  collection,  removal,  and  disposal  of  offal  and  dead  ani- 
mal bodies  is  one  of  the  functions  of  the  municipality,  and  is 
necessary  to  prevent  the  decomposition  of  the  offal  upon  the 
street  and  becoming  a  nuisance  to  public  health.  The  prompt 
removal  in  specially  constructed  wagons  of  the  dead  animal 
bodies  is  done  by  the  health  authorities,  and  the  carcasses  are 
utilized  for  soap  and  other  manufactures,  or  destroyed  under 
the  supervision  of  the  same  authorities. 

Disposal  of  Dead  Human  Bodies. — ^The  necessity  for  prompt 
and  efficient  disposal  of  dead  human  bodies  is  self-apparent. 

The  disposal  of  dead  bodies  may  be  accomplished  by  two 
methods — ^burying  and  cremation. 

The  previous  embalming  or  antiseptic  treatment  of  the 
body  may  be  of  benefit  to  public  health  by  the  effective  de- 
struction of  any  and  all  infective  organisms  within  the  dead 
body. 

Cremation  is  an  efficient  method  of  disposal,  and  has  many 
advantages,  the  principal  one  being  the  destruction  of  the 


172  DISPOSAL  OF  WASTE  MATTER 

bulk  of  the  body,  the  elimination  of  all  possibility  of  any  sub- 
sequent infection  by  the  body,  and  the  general  sanitary  features 
of  the  process.  With  the  scarcity  of  burying  plots  in  large 
cities,  the  general  cremation  of  dead  bodies  is  bound  to 
become  a  more  frequent  method  than  it  is  at  present. 

The  universal  method  employed  hitherto,  with  few  excep- 
tions, is  by  burying  in  the  ground  and  letting  the  soil  and  its 
bacteria  dispose  of  the  organic  parts  of  the  dead  body.  The 
objections  against  burial  of  dead  bodies  is  the  necessity  of 
large  plots  of  land  near  cities  and  the  possibility  of  infecting 
the  air,  soil,  and  water  near  the  burying  plots.  The  question 
of  infecting  the  air  and  the  soil  of  burial  places  is  not  of  so 
much  importance  as  the  undoubted  danger  of  pollution  of 
watercourses  through  the  drainage  of  infective  matter  from 
the  burial  grounds  and  cemeteries  into  near-lying  rivers  and 
watercourses,  which  may  act  as  sources  of  public  water 
supply.  The  transportation  of  bodies  of  those  dying  from 
infectious  diseases  is  also  a  matter  of  sanitary  regulation. 


III.  DISPOSAL  OF  SEWAGE. 

Sewage  is  the  liquid  and  solid  excrementa  mixed  with  water. 

Sewerage  is  the  disposal  of  liquid  and  solid  excrementa 
mixed  with  water  by  means  of  underground  pipes  called 
sewers. 

Drainage  means  the  disposal  of  any  liquids  and  waters  by 
means  of  drains  or  pipes. 

Drainage  is  distinct  from  sewerage,  and  may  have  nothing 
to  do  with  it,  as,  for  instance,  when  a  marsh  or  water-logged 
ground  is  drained  off  by  means  of  canals,  etc. 

The  immediate  disposal  of  sewage  from  houses  has  already 
been  spoken  of  in  the  chapter  on  housing  hygiene. 

The  final  disposal  of  sewage  gained  from  dry  methods  of 
house  disposal  consists  mostly  in  the  utilization  of  the  dry 
sewage  for  fertilizer,  as  the  concentrated  form  of  the  sewage 
is  economically  very  valuable. 


DISPOSAL  OF  SEWAGE  173 

The  final  disposal  of  sewage  gained  from  sewers,  mixed  as 
it  is  with  large  volumes  of  liquids  and  water  from  rains,  etc., 
presents  at  times  more  serious  problems. 

The  disposition  of  sewage  from  sewers  may  be  subdivided 
as  follows : 

1.  Disposal  into  rivers,  lakes,  or  seas. 

2.  Precipitation. 

3.  Filtration  and  irrigation. 

4.  Bacterial  methods. 

1.  The  disposal  of  sewage  into  rivers  and  lakes  may  be  harm- 
less to  public  health,  provided:  (\)  The  amount  of  sewage  is 
small;  (2)  the  volume  of  the  water  in  the  rivers  and  lakes  is 
very  large;  and  (3)  the  rivers  or  lakes  are  not  at  the  same  time 
used  as  a  source  of  water  supply,  either  by  the  community 
disposing  its  sewage  into  them  or  by  any  other  community. 

Small  amounts  of  sewage  are  oxidized  and  made  harmless 
if  diluted  with  large  volumes  of  water,  but  the  danger  of  pol- 
luting the  water  supply  of  towns  by  such  sewage  is  too  great 
to  make  the  practice  of  disposing  of  sewage  into  rivers,  etc., 
sanitary. 

The  disposal  of  contents  of  sewers  into  seas  and  oceans 
would  seem  to  be  of  no  danger  to  public  health,  and  has  been 
regarded  as  a  favorite  and  convenient,  as  well  as  cheap, 
method  of  sewage  disposal  in  all  towns  situated  upon  seas 
and  shores  of  oceans. 

Practically,  however,  it  has  been  demonstrated  that  this 
seemingly  harmless  method  is  not  without  serious  objections 
and  dangers  to  health. 

The  objections  to  sea  disposal  of  sewage  may  be  summed  up 
as  follows: 

(a)  The  bottoms  of  inland  harbors  are  raised  by  the 
accumulations  of  sewage,  and  the  exteriors  of  ships,  etc., 
are  fouled. 

(6)  The  shores  of  health  resorts  on  the  sea  and  the  imme- 
diate surroundings  of  sea-bathing  establishments  are  fouled 
by  the  floating  and  scattered  sewage  matter. 

(c)  The  infection  of  oysters,  fish,  etc.,  with  typhoid  fever 
germs. 


174  DISPOSAL  OF  WASTE  MATTER 

The  fouling  of  the  immediate  neighborhood  of  bathing  es- 
tablishments is  a  serious  danger  to  health,  but  the  greatest 
danger  to  public  health  is,  as  has  been  proved  by  the  investi- 
gations of  Dr.  Soper  and  the  Metropolitan  Sewerage  Com- 
mission of  New  York,  the  possibility  of  infection  of  the  oyster 
crop.  During. 1908,  113  cases  of  typhoid  fever  were  traced 
directly  to  the  ingestion  of  infected  oysters,  which  are  com- 
monly grown  in  polluted  sea  water  near  towns. 

These  and  other  considerations  have  made  the  disposal  of 

I  sewage  into  rivers,  lakes,  and  even  into  seas,  not  desirable 

{  and  injurious  to  public  health,  and  other,  more  effective,  less 

'  harmful,  and  more  scientific  methods  of  final  disposal     of 

the  sewage  from  towns  preferable. 

Methods  of  Sewage  Disposal. — Of  the  older  methods,  the 
more  valuable  are  physical  and  chemical  precipitation,  also 
filtrations  and  intermittent  irrigation.  Of  the  more  modern 
methods,  the  biological  deserves  the  greatest  attention. 

2.  Precipitation. — The  solid  parts  of  the  sewage  may  be 
partly  removed  or  separated  from  the  liquid  mass  by 
mechanical  precipitation  or  sedimentation,  and  the  liquid 
part  may  then  be  drained  off  into  rivers,  etc.,  while  the  solid 
part  is  utilized  in  one  way  or  another.  The  precipitation 
of  the  solid  particles  of  sewage  is  accomplished  either  by 
gravity  in  large  tanks,  at  the  mouths  of  sewers,  or  by  means 
of  screens,  revolving  blades,  and  other  devices. 

Chemical  means  may  be  employed  to  assist  or  to  cause 
precipitation;  and  the  iron  salts,  copper  sulphate,  lime, 
alum,  etc.,  have  been  used  for  thp  purpose  of  forming  floccu- 
lent  precipitates,  which,  on  settling,  are  supposed  to  clarify 
the  sewage  from  most  of  its  solid  and  harmful  parts. 

Intermittent  soil  filtration  has  been  defined  by  the  Metro- 
\  politan  Sewage  Commission  as  "the  concentration  of  sewage, 
^at  short  intervals,  on  an  area  of  specially  chosen  porous 
ground,  as  small  as  will  absorb  and  cleanse  it,  not  excluding 
vegetation,  but  making  the  produce  of  secondary  importance. 
The  intermittency  of  the  application  is  a  si)w  qua  non  even 
in  suitably  constituted  soils  wherever  complete  success  is 
aimed  at." 


DISPOSAL  OF  SEWAGE  175 

Sewage  is  effectively  purified  by  passing  through  soil,  sand, 
gravel,  etc.,  and  this  process  is  not  only  filtration,  but  com- 
plete purificadon,  as  the  soil  acts  biologically  upon  the  organic 
parts  of  the  sewage,  provided  the  filtration  is  not  continuous 
and  the  soil  is  rest^ed  for  certain  inten-als.  As,  however, 
large  filter  beds  are  needed  for  the  disposal  of  large  volumes 
of  sewage  (one  acre  of  filter  bed  for  the  sewage  of  1000  to 
2000  persons),  this  method  is  not  always  practicable  in 
communities  where  land  is  valuable  or  scarce. 

Electricity  has  been  recommended  as  a  means  of  destroying 
or  disinfecting  sewage  matter,  but  so  far  has  not  proved  itself 
of  much  value. 

3.  "Irrigation"  has  been  defined  by  the  Metropolitan  Sewage 
Commission  as  "the  distribution  of  sewage  over  a  large  sur- 
face of  ordinary  agricultural  ground,  having  in  view  a  maxi- 
mum growth  of  vegetation,  consistently  with  due  purification, 
for  the  amount  of  sewage  suplied."  It  is  practically  the  same 
as  filtration,  done  intermittently,  applied  to  garden  and  vege- 
table land,  with  the  purpose  not  only  of  purifying  and  dis- 
posing of  the  sewage,  but  of  utilizing  the  organic  parts  of  the 
sewage  for  fertilizing  purposes  as  well.  This  method  has 
been  used  with  great  success  in  Berlin  and  Paris  and  other 
places.  The  objections  raised  against  this  method  are  partly 
the  same  scarcity  of  land  and,  additionally,  the  possibility, 
proved  in  some  instances,  of  contaminating  the  growing 
vegetables,  etc.,  with  pathogenic  germs  from  the  sewage,  a 
danger  which  is  specially  enhanced  by  the  fact  that  many  of 
the  vegetables  are  eaten  raw. 

Subsoil  irrigation  is  the  same  process,  but  modified,  in  that 
the  sewage  is  conducted  to  the  irrigated  land,  not  super- 
ficially, but  by  means  of  porous  earthenware  drains,  placed  a 
few  inches  underneath  the  ground. 

Both  surface  and  subsoil  irrigation  are  valuable  means 
of  economic  final  disposal  of  sewage,  and  have  been  largely 
adopted  abroad,  but  the  system  does  not  seem  to  find  favor 
in  the  United  States. 

4.  Bacterial  processes  of  sewage  disposal  (biological,  bacterial, 
or  septic  methods)  consist  essentially  of  two  processes. 


176  DISPOSAL  OF   WASTE  MATTER 

First,  the  liquefaction,  dissolution,  and  putrefaction  of  the 
sewage  due  to  the  action  of  the  bacteria  present  in  it,  such 
bacteria  acting  without  the  presence  of  air  or  oxygen,  and 
therefore  called  anaerobic  bacteria.  This  process  consists 
in  placing  the  sewage  in  covered  septic  tanks  or  containers, 
where  the  sewage,  without  the  presence  of  air,  undergoes  a 
process  of  decomposition,  fermentation,  and  putrefaction, 
which  effectively  breaks  up  all  solid  particles,  liquefies  the 
whole  substance,  and  renders  it  favorable  for  the  action  of 
the  next  nitrifying  process. 

The  next  process  is  the  exposing  of  the  liquefied  effluent 
from  the  septic  tanks  to  the  action  of  aerobic  bacteria  by 
running  it  slowly  through  open  sand  filters,  a  modified  process 
of  intermittent  filtration,  which  nitrifies  the  sewage  and  makes 
the  effluent  of  the  filter  beds  entirely  free. from  all  harmful 
matters  and  germs. 

The  various  septic  tanks,  strainers,  filter  beds,  and  other 
works  necessary  for  the  bacterial  sewage  purification  are  very 
complicated,  and  their  erection  is  in  the  province  of  the 
sanitary  engineer. 

There  are  a  number  of  various  patented  processes  of  septic 
sewage  purification,  but  they  are  all  based  on  the  principles 
briefly  stated  above. 

The  great  advantages  of  bacterial  sewage  disposal  is  the  com- 
plete removal  of  sewage  of  every  town  without  respect  to  its 
size,  location  on  rivers,  seas,  etc.,  and  the  effective  destruc- 
tion of  all  harmful  products  in  the  sewage.  Indeed,  it 
has  been  proved  that  the  final  effluent  from  the  filter  beds 
is  capable  of  supporting  the  life  of  fish,  and  even  the  drink- 
ing of  it  has  been  known  not  to  be  followed  by  injurious 
results. 

The  process  is  also  comparatively  economical,  and  disposes 
of  any  and  all  harms  of  the  usual  disposal  of  sewage  into 
rivers,  lakes,  seas,  and  of  any  other  means  of  disposal. 

The  septic  process  of  bacterial  sewage  disposal  is  exten- 
sively employed  in  England,  and  is  rapidly  being  introduced 
in  the  United  States. 


QUESTIONS  177 


QUESTIONS, 

Name  the  various  waste  matters  in  towns  and  villages. 

State  the  quantities  of  each  of  the  waste  matters. 

Describe  the  relations  of  the  various  waste  matters  to  public  health. 

What  are  the  methods  of  disposal  of  rainwater? 

What  are  the  methods  of  disposal  of  snow? 

WTiat  are  the  methods  of  disposal  of  street  refuse? 

What  are  the  methods  of  disposal  of  house  refuse? 

What  are  the  methods  of  disposal  of  dead  animal  bodies? 

What  are  the  methods  of  disposal  of  human  dead  bodies? 

What  are  the  various  methods  of  final  disposal  of  sewage? 

What  are  the  objections  to  ocean,  sea,  and  river  disposal? 

Describe  the  methods  of  disposal  of  sewage  by  intermittent  filtration. 

Describe  the  disposal  of  sewage  by  surface  and  subsoil  irrigation. 

What  are  the  biological  methods  of  sewage  disposal? 

What  are  their  advantages? 


12 


CHAPTER  IX. 
PUBLIC  NUISANCES. 

Definition. — A  public  nuisance  in  the  general  sense  is 
the  use  of  one's  property,  or  an  action  on  the  part  of  a  mem- 
ber of  the  community,  which  may  interfere  with  the  liberty, 
comfort,  or  health  of  other  members  of  the  community. 
An  example  of  such  a  nuisance  may  be  had  in  the  encumber- 
ing by  a  merchant  of  the  sidewalk  before  his  store,  or  the 
obstruction  of  the  street  by  builders  with  accumulation 
of  building  material.  Such  nuisances  do  not  affect  the 
health,  but  interfere  with  the  liberty  and  comfort  of  the 
members  of  the  community,  and  therefore  come  under  the 
head  of  preventable  nuisances. 

A  public  nuisance  or  a  public  health  nuisance  is  limited 
to  such  acts,  etc.,  as  are  detrimental  to  health  or  dangerous 
to  life. 

It  is  not  always  possible  to  prove  the  exact  danger  to 
life  and  injury  to  health  of  certain  nuisances,  and  it  has 
been  regarded  that  even  such  acts  which  are  merely  a 
discomfort  to  other  members  of  the  community  and  only 
remotely  detrimental  to  health  may  also  be  included  under 
the  category  of  nuisances.  Thus  among  the  public  nui- 
sances which  are  regarded  as  coming  under  the  proper 
jurisdiction  of  health  authorities  is  everything  that  produces 
noise,  smoke,  dust,  dirt,  smell,  gases,  and  fumes. 

Any  person,  establishment,  trade,  industry,  etc.,  which 
produces  one  or  more  of  the  nuisances  named  is  thereby 
violating  the  public  health  laws  to  which  he  is  amenable, 
and  is  also  liable  in  case  he  does  not  abate  the  nuisance 
after  due  warning  and  order  by  proper  authorities. 


(178) 


NOISE  AS  A  PUBLIC  NUISANCE  179 


NOISE  AS  A  PUBLIC  NUISANCE. 

As  a  public  nuisance  we  may  regard  the  excessive  noises 
which  characterize  modern  city  hfe. 

A  large  part  of  the  city  noises  are  unavoidable  and  a 
necessary  product  of  the  intense  urban  activity  and  life, 
but  there  are  also  many  noises  which  are  entirely  unnecessary 
and  preventable,  and  hence  a  public  nuisance. 

"VATiile  it  is  not  possible  exactly  to  prove  the  direct  danger 
to  life  or  the  injury  to  health  of  excessive  city  noises,  it  is 
undoubtedly  a  fact  that  these  noises  are  not  without  harmfid 
effects,  if  not  to  healthy  adults,  at  least  to  the  delicate  in 
health,  to  invalids,  sick,  convalescents,  women,  and  children. 
In  such  persons  excessive  noises  interfere  with  sleep  and 
rest,  produce  irritability,  insomnia,  nervous  disturbances, 
neurasthenia,  and  general»debility. 

We  may  also  presume  that  excessive  street  noises  may 
directly  endanger  life  and  limb  by  deafening  pedestrians 
and  preventing  them  from  hearing  danger  signals  and 
thereby  from  avoiding  vehicles,  automobiles,  etc. 

The  causes  of  most  street  city  noises  may  be  classified 
as  fellows: 

1.  Street  pavements. 

2.  Street  traffic. 

3.  Street  ti-ansportation. 

4.  Trades  and  industries. 

5.  Street  vendors,  etc. 

6.  Noisy  persons. 

Street  pavement  noises  are  prolific  and  due  to  the  material 
and  character  of  the  pavement.  Especially  noisy  are  stone 
and  granite  block  pavements,  and  these  become  noisier  with 
age,  wear  and  tear  of  the  stones  and  blocks,  producing  holes 
and  crevices  which  make  much  noise  on  contact  with  vehicles, 
etc.    Wood  and  asphalt  pavements  are  much  less  noisy. 

The  street  trafl&c  noises  are  those  caused  by  the  rumbling 
of  wagons,  the  hoofs  of  horses,  the  wheels  of  the  wagons, 
the  tramping  of  the   feet  of  pedestrians,  and  many  other 


180  PUBLIC  NUISANCES 

similar  causes.  The  greatest  part  of  street  noises  is 
undoubtedly  due  to  the  means  of  transportation,  to  the 
horse,  steam,  and  electric  cars  and  tramways,  the  rails, 
the  crossings,  and  the  terrific  noises  made  by  the  heavily 
loaded  cars  upon  the  iron  rails  and  crossings,  especially 
when  those  rails  are  loose,  the  car  wheels  worn  and  flat, 
and  the  street  crossed  and  recrossed  by  a  network  of  loose 
rails  and  switches 

The  noises  of  various  industries,  such  as  blacksmiths,  lumber 
mills,  machine  shops,  boiler  works,  printing  presses,  etc.,  need 
no  description. 

Other  unnecessary  additions  to  the  pandemonium  of 
city  noises  are  furnished  by  the  multitudinous  street  pedlers, 
hawkers,  criers,  fiddlers,  organ-grinders,  orchestras,  etc. 

Finally,  the  Babel  of  city  noises  is  much  augumented 
by  the  population  itself  and  its  extraordinary  vociferations 
during  work,  pleasure,  or  play,  and  especially  the  young 
generation,  who  consider  their  greatest  pleasure  to  be  in 
the  most  noise  they  produce. 

Among  the  avoidable  noises  we  may  regard  some  of  the 
following:  ^ATiistling  of  factories,  ringing  of  church  bells, 
noises  caused  by  defects  in  street  pavements,  by  defects 
of  cars  and  means  of  transportation,  by  loose  rails  and 
flat  wheels,  by  transportation  of  rails  and  iron  on  wagons, 
by  the  street  noises  of  pedlers  and  hawkers  and  street 
musicians,  or  by  some  of  the  industrial  processes. 

The  prevention  of  city  noises  may  be  accomplished  by 
many  of  the  following  measures : 

1.  Education  of  the  public  in  the  harm  of  unnecessary 
noises. 

2.  Municipal  legislation  prohibiting  excessive  noises. 

3.  Prohibition  of  street  music,  cries  of  pedlers,  wagon 
bells,  etc. 

4.  Substitution  of  stone  pavements  by  asphalt  and  wood. 

5.  Compelling  all  wagons,  etc.,  to  have  rubber  tires 
and  good  springs. 

6.  Removing  of  all  noisy  industries  from  residential 
districts. 


DUST  AS  A   PUBLIC  NUISANCE  181 

7.  Supervision  of  street  rails  and  cars  and  other  means 
of  transition. 

S.  Removal  of  children,  etc.,  from  streets  by  provision 
of  playgrounds,  parks,  etc. 

SMOKE  AS  A  PUBLIC  NUISANCE. 

Sources. — The  black  smoke  which  is  belched  forth  by 
so  many  establishments  in  large  cities  is  a  source  of  public 
nuisance,  not  without  effect  upon  public  health. 

The  composition  of  the  smoke  as  it  leaves  the  chimneys 
varies  and  depends  on  the  kind  and  character  of  the  fuel 
and  on  the  methods  of  combustion. 

Smoke  is  the  unconsumed  part  of  the  fuel,  and  consists 
of  suspended  carbon  particles  with  an  admixture  of  various 
gases,  such  as  hydrogen,  carbonic  acid,  sulphur,  etc. 

Smoke  is  a  nuisance  because  it  contaminates  the  air  by 
the  addition  of  impurities,  darkens  the  streets,  causes  fogs, 
discolors  all  house  and  street  surfaces,  smirches  laundry 
and  clothes,  interferes  with  ventilation  of  houses  by  the 
disinclination  of  householders  to  open  the  windows,  and 
causes  a  cheerless,  sombre  city  appearance. 

The  smoke  nuisance  may  be  prevented  by  compulsory 
use  of  hard  instead  of  soft  coal,  by  proper  methods  of  com- 
bustion, by  installation  of  smoke  consumers,  and  similar 
mechanical  improvements. 


DUST  AS  A  PUBLIC  NUISANCE. 

Sources. — Large  amounts  of  dust  are  produced  by  house- 
holds, by  processes  of  street  cleaning,  and  by  industrial 
establishments. 

Prevention. — The  dust  produced  by  households,  such 
as  beating  of  carpets,  rugs,  etc.,  may  be  prevented  by  proper 
sanitary  regulation  and  prohibitions  to  beat  carpets  in 
streets,  etc.,  also  by  improved  methods  of  housing  sanitation, 
by  vacuum  cleaners,  etc. 


182  PUBLIC  NUISANCES 

The  provision  of  water-sprinkling  machines,  or  the  use  of 
oil  and  other  dust-laying  fluids,  the  use  of  improved  cleaning 
machinery,  covered  carts,  etc.,  may  eliminate  some  of  the 
worst  features  of  present  street  cleaning. 

All  industries  creating  excessive  dust  should  be  removed 
from  the  city  precincts,  and,  besides,  should  be  compelled 
to  provide  themselves  with  means  of  controlling  the  dust, 
utilizing  and  collecting  the  same.-  Many  dusty  processes 
of  carpet-beating,  sand-blasting,  and  other  dust-producing 
establishments  have  been  eliminated  by  more  modern  methods 
of  industry,  vacuum  methods  of  cleaning,  etc. 


WASTE  MATTERS  AS  PUBLIC  NUISANCES. 

Sources.— Mention  has  been  made  already  of  the  nuisance 
caused  by  various  industries  in  which  a  large  quantity  of 
waste  is  produced  and  this  waste  then  disposed  of  into 
the  public  water  supply  system  or  any  water  courses  which 
may  serve  as  such. 

The  number  of  such  industries  is  large,  and  such  a  dis- 
posal of  their  waste  matter  may  be  regarded  as  a  public 
health  nuisance.  Sugar  refineries;  breweries;  paper,  starch, 
gas,  alkali,  color,  chemical,  and  other  works;  tanneries; 
laundries;  oil  and  other  factories  are  among  the  many  which 
thus  become  a  nuisance  by  the  improper  disposal  of  their 
waste  matters. 

Prevention. — ^The  abatement  of  the  nuisance  may  be 
accomplished  by  strict  legislation  and  compulsory  installa- 
tion of  waste-consuming  and  waste-reducing  plants  in  each 
of  the  mentioned  industries. 


GASES  AND  FUMES  AS  PUBLIC  NUISANCES. 

Sources. — A  prolific  cause  of  public  nuisance  in  com- 
munities are  the  many  industries  in  which  various  delete- 
rious gases  and  fumes  are  evolved. 


GASES  AND  FUMES  AS  PUBLIC  NUISANCES      183 

The  gases  and  fumes  which  are  evolved  by  various  trades, 
and  which  may  be  regarded  as  public  nuisances  because 
of  their  harmful  effects  on  their  surroundings  and  on  human 
beings,  are  sulphur,  sulphuric  acid,  sulphuretted  hydrogen, 
carbon  monoxide,  coal  gas,  water  gas,  chlorine,  bromine, 
ammonia,  and  others. 

Among  the  offensive  trades  evolving  some  of  the  fore- 
going gases  are  the  color,  dye,  and  chemical  works  in  gen- 
eral, lead,  arsenic,  soda,  potash,  alkali,  petroleum,  coal-tar 
and  an  infinite  number  of  other  similar  manufactures;  also  the 
manufactm-e  of  illuminating  gas,  the  various  metal  works,  etc. 

Such  trades  are  commonly  designated  as  "offensive," 
and  do  become  a  "public  nuisance"  when  their  gases, 
fumes,  and  odors  interfere  with  the  health  and  comfort  of 
the  community  in  which  they  are  situated. 

The  harm  of  ofiensive  trades  cannot  always  be  fully  deter- 
mined, but  may  be  summed  up  in  the  following:  Offensive 
and  foul  odors  vitiating  the  air  of  the  neighborhood  near 
the  works,  destruction  of  vegetation  in  the  neighborhood, 
and  the  direct  effect  of  the  injurious  gases. 

Prevention. — The   prevention   of   the    above   works   from 
becoming  a  public  nuisance  is  within   the  province  of  the 
sanitarv  engineer,   who   is   to  devise   for   each   industrv   a 
specially  fitted  form  of  prophylaxis,  destruction  and  elimina- 
tion of  its  injurious  gases,  etc. 

The  following  measures  may  be  regarded  as  a  resume 
of  the  sanitary  control  of  offensive  trades  likely  to  become 
public  nuisances: 

1.  Municipal  control,  supervision,  and  license. 

2.  Restriction  of  territory  within  which  any  offensive  trades 
may  be  located,  and  removal  of  specially  offensive  trades  from 
inhabitable  portions  of  the  town. 

3.  Dilution  of  the  offensive  gases  and  fumes  by  large 
volumes  of  air,  by  the  construction  of  very  tall  chimneys 
conducting  the  deleterious  gases  high  into  the  external  air. 

4.  Condensation  of  deleterious  gases,  etc.,  by  water 
coolers,  or  by  passing  the  gases  through  water-filled  con- 
densers, or  wet  coke  scrubbers,  etc. 


184  PUBLIC  NUISANCES 

5.  Absorption  of  the  gases  in  fire-pits,  where  they  may 
be  destroyed  by  the  action  of  fire  or  by  passage  through 
some  neutralizing  substance,  which  is,  of  course,  different 
for  each  gas. 

6.  Constant  inspection  of  such  offensive  trades  by  com- 
petent, techincally  educated  inspectors,  who  shall  note  the 
exact  causes  of  the  nuisance  and  suggest  proper  remedies. 


ODORS,   EFFLUVIA,   ETC.,   AS   PUBLIC  NUISANCES. 

Sources. — The  greatest  number  of  the  so-called  offensive 
trades  become  a  public  nuisance  through  the  odors  and 
offensive  efHuvia  produced  by  them. 

It  is  not  always  possible  to  determine  the  harmful  effects 
of  offensive  odors  on  health.  Indeed,  it  is  doubtful  if  the 
offensive  odor  by  itself  is  capable  of  causing  sickness  or 
injury  to  the  health  of  a  robust  normal  person.  Never- 
theless, it  is  regarded  by  almost  all  civilized  communities 
that  the  production  of  offensive  odors  constitutes  a  public 
nuisance,  the  abatement  of  which  devolves  upon  the  sanitary 
authorities. 

While  it  is  true  that  it  is  difficult  to  prove  the  harmful 
effects  of  offensive  odors  upon  robust  adult  persons,  it  is 
less  difficult  to  prove  such  deleterious  effects  upon  invalids, 
upon  convalescents,  upon  those  suffering  from  various 
diseases,  and  upon  all  persons  in  whom  interference  with 
free  enjoyment  of  breathing,  with  sleeping,  and  with  rest 
may  produce  harmful  effects.  It  is  certainly  true  that 
such  an  interference  does  take  place  in  the  presence  of 
offensive  odors,  and  such  an  interference  with  breathing, 
sleep,  and  rest  may  become  not  only  injurious,  but  fatal 
in  some  cases. 

Moreover,  most  industries  which  produce  offensive  odors 
do  so  by  the  production  of  organic  waste  matter,  which, 
by  its  putrefaction,  evolves  foul  odors,  and  the  organic  matter 
by  itself  may  become  a  source  of  public  nuisance  aside  of 
its  odors. 


ODORS  AND  EFFLUVIA  AS  PUBLIC  NUISANCES     185 

The  classes  of  offensive  trades  which  may  become  a  public 
nuisance  because  of  their  odors  and  organic  waste  matter 
may  be  stated  in  four  divisions : 

1.  The  keeping  of  Hve  animals. 

2.  The  killing  of  animals. 

3.  The  sale  of  animal  matter. 

4.  The  manufacture  of  animal  products. 

1.  The  Keeping  of  Animals. — The  nuisance  caused  by 
keeping  live  animals  in  stables,  etc.,  in  cities  may  be  due 
to  the  specific  odors  emanating  from  the  animals,  to  the 
odors  of  urine,  excreta,  and  other  waste  matters,  to  the 
noises  created  by  them,  to  the  flies  and  parasites  attracted 
by  them,  and  finally  to  the  possible  germs  likely  to  be  trans- 
mitted by  them. 

All  sanitary  codes  and  municipal  sanitary  regulations 
contain  detailed  rules  intended  to  control  and  abate  the 
nuisance  caused  by  the  keeping  of  live  animals. 

The  essence  of  most  of  the  sanitary  legislation  of  the  keep- 
ing of  live  animals  to  abate  its  nuisances  may  be  summed 
up  in  the  following  measures: 

(a)  State  veterinary  supervision  of  domestic  animals. 

(b)  Prohibition  of  keeping  certain  animals  within  city 
districts. 

(c)  Restriction  of  places  to  certain  districts,  etc. 

(d)  Sanitary  supervision  of  construction  of  stables,  etc. 

(e)  Rules  about  removal  of  manure  and  sanitation  of 
stables. 

In  New  York,  for  instance,  certain  animals,  such  as  pigs, 
goats,  etc.,  are  not  allowed  to  be  kept  within  the  city  limits, 
and  when  kept  in  outlying  districts  must  be  licensed.  Nor 
are  such  animals  allowed  to  be  kept  in  tenement  houses, 
nor  the  building  of  stables  on  tenement  house  lots,  and 
the  keeping  of  chickens,  pigeons,  etc.,  require  permit  from 
the  Health  Department.  In  Boston,  stables  are  prohibited 
within  200  feet  from  a  church.  In  Chicago  it  is  necessary 
for  the  erection  of  a  stable  to  get  the  permission  of  the  owners 
of  the  property  within  600  feet  from  the  proposed  stable. 

The  storage  and  keeping  of  animal  matter,  such  as  manure, 


186  PUBLIC  NUISANCES 

offal,  refuse,  bones,  garbage,  may  also  become  a  public 
nuisance  by  the  odors,  the  putrefaction,  and  the  decomposi- 
tion, etc.,  caused  by  them,  and  hence  sanitary  regulations 
include  the  keeping  of  animal  matters  among  the  offensive 
trades. 

All  sanitary  authorities  demand  that  the  removal  of  all 
manure  and  animal  matter  be  very  prompt,  thorough,  and 
periodical,  and  that  it  should  be  done  at  certain  hours, 
during  which  the  process  of  removal  is  not  likely  to  become 
a  nuisance. 

The  immediate  destruction  of  all  animal  matter,  prompt 
removal,  and  cleaning  and  disinfection  of  premises  are  the 
most  approved  measures  to  abate  the  nuisance. 

2.  The  Killing  of  Animals. — The  killing  of  animals  for 
food  purposes  is  one  of  the  oldest  industries  in  the  world, 
and  when  done  in  special  establishments  within  city  limits 
may  become  a  public  nuisance  by  reason  of  the  odors  from 
the  killed  animals  and  by  reason  of  several  other  features 
of  every  such  establishment,  such  as  noise,  presence  of 
animal  matter,  blood,  decomposition,  and  the  flies  and 
parasites  which  such  decomposition  may  attract. 

The  principal  nuisance  of  slaughter  houses  is  due  to  the 
large  quantities  of  organic  matter  which,  if  not  immediately 
removed,  becomes  decomposed  and  emits  foul  odors,  and, 
moreover,  may  contaminate  fresh  animal  foods. 

The  common  prophylactic  measures  are  about  the  same 
as  those  for  keeping  live  animals:  Restriction  of  slaughter 
houses  to  special  districts,  construction  of  municipal 
abattoirs,  the  construction  of  abattoirs  with  all  inside 
surfaces  made  of  non-absorbent  material,  the  utilization 
of  all  blood  and  other  by-products,  the  provision  for  the 
use  of  large  quantities  of  water,  and  a  complete  sanitary 
supervision  of  all  the  features  of  such  places,  so  as  to  make 
the  industry  odorless  and  harmless. 

Municipal  provisions  about  slaughter  houses  were  inaugu- 
rated in  the  United  States  as  early  as  in  1692,  in  Boston, 
and  at  present  they  are  a  feature  of  the  sanitary  code  of 
every  municipality.    The  construction  of  municipal  abattoirs 


ODORS  AND  EFFLUVIA  AS  PUBLIC  NUISANCES      187 

would  eliminate  the  nuisance  created  by  private  slaughter 
houses,  as  such  abattoirs  would  be  superior  in  their  con- 
struction and  be  maintained  in  a  better  sanitary  condition 
than  those  carried  on  by  private  interests. 

3.  The  Sale  of  Animal  Products  and  Food. — The  establish- 
ments where  various  animal  matter,  food,  etc.,  are  sold  may 
also  become  a  public  nuisance  by  reason  of  the  odors  created 
by  such  animal  food,  etc.,  also  by  reason  of  the  possible 
decomposition  of  the  organic  matter,  the  flies  and  para- 
sites which  they  attract,  and  the  possible  source  of  infection 
of  the  food  and  transmission  to  those  who  use  it  as  food. 

Among  the  ofEensive  food  trades,  or  rather  trades  which  may 
become  offensive,  may  be  included  the  following:  butcher 
stores,  fish  markets,  fruit  and  vegetable  stalls,  public  markets, 
grocery  stores,  restaurants,  etc. 

The  sources  of  nuisance  from  most  of  these  industries 
consist  mostly  in  the  exposure  of  animal  and  easily  decom- 
posing matter  in  the  open  at  temperatures  which  favor 
decomposition  and  also  permit  the  depositing  of  dust  and 
street  dirt  upon  the  edible  stuffs.  They  also  consist  in 
the  exposure  to  putrefaction  of  remnants  of  food  which 
allows  the  gathering  of  flies,  insects,  animals,  etc.,  and 
the  emanation  of  foul  and  offensive  odors. 

Regulation. — ^The  means  of  controlling  places  where 
food  and  animal  matter  are  exposed  for  sale  consist  in  the 
following  measures: 

(a)  Restriction  of  sale  of  fish,  meat,  and  such  products 
to  centrally  located  public  markets. 

(6)  The  sanitary  control  of  private  establishments. 

(c)  The  proper  construction  of  such  markets  and  shops 
with  abundant  ventilation  and  light,  with  solid,  impervious, 
and  non-absorbent  walls,  ceilings,  and  fioors  properly  graded 
and  drained,  made  of  solid  non-pervious  and  washable 
material,  and  with  means  of  profusely  flushing  the  premises 
with  water  and  of  keeping  them  at  a  temperature  low  enough 
to  inhibit  the  development  of  bacteria  and  decomposition. 

(d)  Sanitary  supervision  and  inspection  of  public  and 
private  establishments. 


188  PUBLIC  NUISANCES 

5.  Manufacture  and  Utilization  of  Animal  Substances. — Finally 
there  is  a  group  of  industries  which  are  based  on  the  utiliza- 
tion of  animal  substances  for  various  purposes  and  the 
manufacture  from  them  of  certain  products,  such  industries 
coming  under  the  classification  of  offensive  trades  because 
of  the  nuisance  created  during  some  processes  of  their  work. 

Such  offensive  trades  include  lard  refining,  fat  rendering, 
blood  and  bone  boiling,  glue  making,  gut  cleaning,  the 
manufacture  of  soap,  glycerin,  etc.,  the  preparation  and 
tanning  of  skins  and  hides,  boiling  of  oil,  making  of  var- 
nishes, etc. 

The  specific  nuisance  created  in  each  of  the  above-named 
industries  varies  according  to  such  circumstances,  as  the 
substances  used,  the  products  manufactured,  the  processes 
employed,  and  a  number  of  other  factors. 

The  cardinal  source  of  nuisance  lies  in  the  odors  and  effluvia 
created  in  those  establishments,  an  odor  which  usually 
penetrates  far  from  the  place  of  manufacture,  and  may 
become  offensive  to  the  inhabitants  of  the  neighborhood. 

Besides  the  odor,  there  are  also  in  each  of  the  enumerated 
trades  some  other  offensive  elements  which  also  may  render 
those  establishments  a  public  nuisance. 

The  principles  of  prophylaxis  are  the  same  in  these  as  well 
as  in  other  offensive  trades  with  special  measures  indicated 
in  each  special  establishment. 

The  most  important  prophylactic  measure  is  the  pro- 
hibition of  carrying  on  these  and  any  other  offensive  trades 
within  the  residential  districts,  and  concentration  of  them 
in  special  places  far  removed  from  living  habitation.  This 
applies  especially  to  such  trades  as  hide  tanning,  glue 
making,  soap  manufacture,  etc. 

The  next  important  prophylactic  measure  is  the  licensing 
of  such  establishments  by  municipal  sanitary  departments, 
in  order  that  a  complete  supervision  may  be  had  of  their 
construction  and  maintenance. 

The  proper  construction  of  any  factory  where  substances 
likely  to  become  offensive  are  manufactured  must  be  under 
the    supervision     of    sanitary     engineers.     The     buildings 


QUESTIONS  189 

must  be  made  of  hard,  solid,  non-absorbent  material,  with 
smooth,  impervious  inside  surfaces,  and  with  a  special 
provision  for  natural  and  artificial  light,  ventilation,  water 
supply,  and  drainage. 

A  great  many  of  the  offensive  substances  and  processes 
in  many  of  the  above  industries  are  not  absolutely  necessary, 
and  may  advantageously  be  substituted  by  less  offensive 
methods,  etc. 

The  use  of  tight  vessels  for  the  holding  of  all  animal 
matter,  the  removal  of  all  accumulated  remnants  and  un- 
used parts,  the  absolute  cleanliness  in  all  processes,  and 
the  copious  use  of  water  are  other  prophylactic  measures. 

Another  most  important  prophylactic  measure  is  the 
destruction  of  all  odors  by  proper  mechanical  devices,  such 
as  their  destruction  by  fire,  by  special  condensers,  etc., 
devices  which  may  greatly  abate  the  odors  and  the  con- 
sequent public  nuisance  of  such  establishments. 

The  prevention  of  the  disposal  of  the  various  waste  matters, 
sludge,  etc.,  from  any  of  the  above  industries  is  a  necessary 
prophylactic  measure  against  the  pollution  of  watercourses 
and  streams. 

QUESTIONS. 

Give  the  definition  of  public  nuisance. 

Name  the  common  public  nuisances. 

State  the  causes  of  city  noises,  their  effects  and  prevention. 

Give  the  causes,  effects,   and  means  of  prevention  of  smoke. 

Give  the  causes,  effects,  and  means  of  prevention  of  dust  in  cities. 

Give  the  causes,  effects,   and  prevention  of  gases  and  fumes. 

Name  trades  consisting  in  keeping  live  animals,  the  nuisance  produced 
by  the  same,  and  rules  governing  such  trades. 

Name  trades  consisting  in  killing  of  animals,  the  nuisances  produced 
by  the  same,  and  rules  governing  such  trades. 

Name  the  trades  consisting  in  the  sale  of  animal  matter  and  nuisances 
produced  by  the  same,   also  rules  governing  same. 

Name  trades  consisting  in  the  manufacturing  of  animal  products,  the 
nuisances  produced,  and  rules  governing  such  trades. 


CHAPTER  X. 

THE  PREVENTION  OF  INFECTIOUS  DISEASES. 

I.  DEFINITIONS,  CAUSES,  AGENTS,  METHODS,  AND 
MODES  OF  INFECTION. 

Upon  examining  the  recorded  causes  of  death  we  find 
but  a  very  small  percentage  of  deaths  due  to  old  age:  2 
per  cent,  in  the  registration  area  of  the  United  States  during 
1907,  and  but  1.4  per  cent,  in  the  city  of  New  York  for 
the  first  half  of  the  year  1909. 

During  1907  there  were  in  the  same  area  7.6  per  cent,  of 
the  deaths  due  to  violence,  so  that  over  90  per  cent,  of  all 
deaths  were  due  to  disease. 

Disease  is  defined  as  an  antithesis  of  health,  and  as 
"a  condition  of  the  body  marked  by  inharmonious  action 
of  one  or  more  of  the  various  organs  or  tissues,  owing  to 
abnormal  conditions  or  to  structural  change." 

Diseases  are  classified  variously  according  to  various 
factors,  etiological  or  symptomatic,  but,  according  to  Sedg- 
wick, they  may  be  classed  into  two  principal  groups — 
constitutional  and  environmental. 

Constitutional  diseases  are  such  as  are  due  to  intrinsic, 
organic,  and  structural  defects  in  the  body  mechanism, 
such  as  diseases  of  circulation,  digestion,  metabolism,  etc. 

Environmental  diseases  are  due  to  extrinsic  factors,  external 
interference,  and  to  the  invasion  of  the  body  by  morbific 
agents. 

Relation  of  Hygiene  and  Disease. — The  prevention  of 
all  disease,  constitutional  as  well  as  environmental,  is  the 
aim  and  function  of  general  hygiene. 

The  prevention  of  constitutional  diseases  is  the  aim  and 
function  of  personal  hygiene. 
(190) 


DEFINITIONS  AND  MODES  OF  INFECTION       191 

The  prevention  of  environmental  diseases  is  within  the 
function  of  public  hygiene,  because  the  etiological  environ- 
mental factors  are  those  usually  acting  in  large  groups 
and  upon  large  masses  of  people,  and  also  because  the 
prevention  of  such  diseases  is  possible  with  the  cooperation 
of  large  bodies  and  communities. 

The  most  important  environmental  diseases  are  those  which 
are  termed  variously  infectious,  communicable,  contagious, 
parasitic,  zymotic,  zymotoxic,  germ,  specific,  etc.,  but  which 
we  shall  include  under  the  one  term,  infectious  diseases. 

Infectious  diseases  are  such  as  are  due  to  the  entrance 
into  the  body  of  certain  microorganisms  of  animal  or 
vegetable  origin.  These  microorganisms  live,  develop, 
reproduce,  increase,  and  produce  certain  toxic  products, 
which  all  cause  certain  groups  of  symptoms  and  patho- 
logical changes,  which  constitute  the  specific  infectious 
disease,  the  chief  characteristic  of  which  is  that  it  may 
be  transmitted  from  one  person  to  another  person,  and 
carried  from  one  place  to  another. 

This  transmission,  infection,  or  communication  of  one 
disease  from  one  individual  to  another  may  be  direct,  or 
indirect,  by  contact  or  through  the  medium  of  certain  objects, 
in  one  way,  or  in  another,  or  in  several  ways  combined. 

Infectious  diseases  are  also  characterized  by  having 
certain  stages,  such  as  exposure,  infection,  invasion,  incuba- 
tion, acme,  decline,  etc. 

The  stage  of  exposure  is  the  time  during  which  the  person 
is  exposed  to  the  presence  of  morbific  agents. 

The  period  of  infection  is  the  period  of  actual  entrance 
of  the  morbific  agents  into  the  organism  or  system. 

The  stage  of  incubation  is  the  period  of  the  actual  develop- 
ment of  the  morbific  agents  within  the  organism,  or  the 
period  of  the  active  struggle  for  existence  between  the 
infecting  agent  and  the  defensive  forces  of  the  body. 

The  period  of  invasion  is  the  period  during  which  the 
infecting  morbific  agents,  having  won  their  battle,  the 
definite  symptoms  of  disease  (the  prodromal  stage),  begin 
to  manifest  themselves. 


192  PREVENTION  OF  INFECTIOUS  DISEASES 

The  stages,  acme,  decline,  and  convalescence,  are  char- 
acterized by  the  height,  dedine  of  disease,  and  the  recovery. 

The  degree  of  infection  depends  on  the  number  of  the 
morbific  agents,  their  virulence,  the  mode  of  entrance,  and 
the  vital  resistance  of  the  body. 

The  incubation  period  depends  on  the  specific  character 
of  the  invading  morbific  agents,  and  varies  with  different 
diseases. 

Decline  of  the  disease  is  either  sudden — by  crisis — or 
gradual — by  lysis.  Convalescence  may  also  be  delayed  by 
"recurrence"  or  "relapse." 

The  disease  may  also  be  of  acute,  subacute,  or  chronic, 
severe  or  mild,  remittent  or  intermittent. 

Infectious  diseases  are  termed  endemic  diseases  when 
they  appear  continuously  in  one  locality,  epidemic  when 
they  effect  a  large  number  of  persons  at  one  time,  and 
pandemic  when  they  cover  a  vast  area  of  land  or  several 
countries. 

The  three  most  important  features  of  infection  and  infec- 
tious disease  which  must  be  studied  for  a  clearer  compre- 
hension of  the  etiology  of  these  diseases,  are  the  following: 

1.  The  morbific  agents. 

2.  The  portals  of  entry. 

3.  Modes,  vehicles,  and  agents  of  transmission. 

1.  Morbific  Agents. — The  belief  that  certain  diseases  are 
caused  by  some  living  agents  outside  of  the  body  is  old 
and  has  been  held  by  many  ancient  observers,  but  the 
proof  has  become  possible  after  the  perfection  of  the  micro- 
scope and  with  the  extensive  research  into  the  micro- 
organic  world  which  this  instrument  has  made  possible. 

To  Pasteur,  of  France,  and  to  Koch,  of  Germany,  we 
owe  the  establishment  upon  a  scientific  basis  of  the  new 
Science  of  Bacteriology,  to  the  researches  in  which  we  owe 
the  definite  proof  that  certain  diseases  are  directly  caused 
and  are  due  to  specific  microorganisms,  which  invade  and 
infect  the  human  body  and,  by  their  activity  and  products, 
cause  the  pathological  changes  and  train  of  symptoms 
which  we  call  infectious  diseases. 


DEFINITIONS  AND  MODES  OF  INFECTION        193 

The  microorganisms  which  act  as  morbific  agents  of 
disease  are  of  animal  or  vegetable  origin,  mostly  of  the 
latter. 

The  animal  parasites  belong  to  the  protozoa,  insects,  and 
worms. 

The  vegetable  microorganisms  are  grouped  under  the 
general  name  of  bacteria,  which  signify  minute  unicellular 
plants,  and  which  are  subdivided  into  a  number  of  groups 
and  types;  one  important  subdivision  being  according  to 
their  external  form;  thus,  the  cocci  are  so  named  because 
of  their  spherical  form,  the  bacilli  have  a  rod-like  elongated 
form,  while  the  spirilli  have  a  spiral  form. 

While  millions  of  these  vegetable  microorganisms  are 
entirely  innocuous,  there  are  among  them  certain  species 
which,  entering  under  favorable  conditions  into  favorable 
soil  in  the  human  organisms,  become  pathogenic  and  are 
to  be  looked  upon  as  the  morbific  agents  of  disease. 

Among  the  more  important  pathogenic  cocci  are  the  follow- 
ing; staphylococcus  pyogenes  aureus,  streptococcus  pyogenes, 
pneumococcus,  and  the  gonococcus. 

The  following  are  some  of  the  pathogenic  bacilli:  bacillus 
anthracis,  bacillus  cedematis  maligni,  bacillus  tetani,  bacil- 
lus typhosus,  bacillus  tuberculosis,  bacillus  mallei,  bacillus 
lepra,  bacillus  diphtherice,  bacillus  influenzoB,  bacillus  coli 
communis. 

Among  the  spirilla  the  following  are  noted:  vibrio  cholera 
asiatica,  spirillum  of  relapsing  fever,  spirochceta  pallida 
(treponema  pallidum). 

Bacterial  Diseases. — Some  of  the  diseases  the  morbific 
agents  of  which  have  already  been  demonstrated  are  the 
following:  septicemia  and  pyemia,  pneumonia,  gonorrhea, 
anthrax,  malignant  edema,  tetanus,  typhoid  fever,  tuber- 
culosis, bubonic  plague,  diphtheria,  influenza,  cholera, 
relapsing  fever,  yellow  fever,  malaria,  syphilis,  etc. 

Some  of  the  diseases  which  are  infectious,  but  the  specific 
agents  of  which  have  not  yet  been  absolutely  demonstrated, 
are  the  following:     scarlet  fever,  measles,  smallpox,  rabies, 
pertussis,  etc. 
13 


194  PREVENTION  OF  INFECTIOUS  DISEASES 

The  pathogenic  action  of  the  morbific  agents  upon  the 
body  may  be  due  partly  to  mechanical,  partly  biological, 
and  partly  chemical  action. 

The  very  presence  of  the  morbific  agents  may  mechanically 
interfere  with  the  physiological  action  of  certain  organs, 
causing  stasis,  hemorrhage,  etc.,  or  the  increased  activity 
of  the  morbific  agents  may  cause  local  inflammation  of 
tissues,  infiltrations,  and  abscesses,  or  the  whole  body  may 
be  infected  by  metastatic  foci  by  means  of  blood  or  lymph, 
thus  carrying  infection  to  remote  parts. 

A  most  important,  if  not  the  greatest,  harm  is  done  not 
by  morbific  agents  themselves,  but  by  their  chemical  products, 
or  toxins  which  are  the  results  of  the  bacterial  action  upon 
the  blood  and  body  fluids,  as  well  as  to  other  bacterial 
products — endotoxins,  proteins,  etc. 

These  toxins  are  not  as  yet  all  known,  and  vary  in  their 
effects  and  virulence  according  to  various  factors. 

2.  Portals  of  Entry. — Infection  of  the  body  with  micro- 
organisms is  by  means  of  entrance  of  these  organisms  into 
the  body  through  certain  portals  of  entry,  which  differ  with 
each  specific  bacterium,  so  that  some  bacteria  may  be 
entirely  innocuous  when  entering  a  certain  organ  of  the 
body  while  pathogenic,  and  virulent  when  entering  another 
part  or  organ. 

The  principal  ports  of  entry  are  the  skin,  the  respiratory, 
the  alimentary,  and  the  genito-urinary  tracts  of  the  body. 

While  some  microorganisms  may  enter  the  healthy  and 
normal  skin,  this  is  very  rare,  and  the  commonest  mode 
of  entrance  is  through  some  solution  of  continuity,  through 
cuts,  bruises,  abrasions,  wounds,  etc. 

The  skin  as  port  of  entrance  admits  certain  animal  para- 
sites, like  favus,  scabies,  tinea  tonsurans;  also  through 
bites  of  insects  in  malaria,  yellow  fever,  plague,  through 
wounds,  etc.,  in  syphilis,  septicemia,  smallpox,  etc. 

The  respiratory  tract  as  port  of  entrance  admits  through 
the  mucous  membranes  of  the  nose,  eyes,  ears,  mouth,  and 
throat,  diphtheria,  scarlatina,  measles,  influenza,  pneumonia, 
etc.     The  throat,  bronchi,  trachea  and  larynx,  and  lungs 


DEFINITIONS  AND  MODES  OF  INFECTION        195 

may  be  the  port  of  entrance  of  tuberculosis,  diphtheria, 
pneumonia,  influenza,  pertussis,  etc. 

The  alimentary  canal  as  the  port  of  entrance  is  open  to 
typhoid,  cholera,  dysentery,  etc. 

The  genito-urinary  tract  as  the  port  of  entrance  is  entered 
by  gonorrhea,  syphilis,  chancroid,  tuberculosis,  diphtheria, 
septicemia,  etc. 

The  different  parts  and  tissues  of  the  body  react  variously 
to  microorganisms,  while  the  various  microorganisms  have 
each  a  predilection  for  certain  parts  of  the  body,  in  some 
of  which  they  thrive,  while  in  others  they  succumb. 

3.  Modes,  Vehicles,  and  Agents  of  Transmission  of  Infectious 
Organisms. — The  pathogenic  bacteria  are  not  found  free 
in  nature,  but  they  live  in  the  body,  the  blood,  the  secretions 
and  excretions,  the  discharges  of  the  body,  the  skin  and 
the  exteriors  of  persons  which  they  infect.  Hence  the 
principal  agent  of  infection,  as  well  as  vehicle  of  transmission, 
is  man  himself  and  animals,  and  their  discharges. 

The  morbific  agents  are  found  in  the  various  parts  and 
discharges  of  the  body.  Thus,  certain  bacteria  may  be 
found  on  the  skin,  in  the  secretions  of  the  eye,  ear,  nose, 
and  throat,  the  sputum,  the  expectoration,  the  perspiration 
of  the  skin,  the  urine,  the  solid  excreta,  the  secretions  from 
wounds  and  abscesses,  etc.  All  the  above-named  secre- 
tions and  excretions  may  contain  virulent  morbific  agents 
which  may  be  transmitted  from  one  individul  to  another. 

The  transmission  of  bacteria  may  be  direct  or  indirect, 
by  contact,  or  by  intermediary  agents  and  vehicles. 

Anything  and  anybody  that  may  take  up  part  of  the 
secretions  and  excretions  from  an  infected  person  and  carry 
them  to  a  non-infected  person  may  serve  as  vehicle  and  agent 
of  infection.  Persons,  animals,  insects,  food,  milk,  water,  air, 
soil,  and  fomites  may  be  then  regarded  as  vehicles  of  infection. 

The  most  frequent,  and  demonstrated,  mode  of  infection 
is  by  direct  contact  of  disease  with  the  healthy,  of  the  persons 
surrounding  the  infected  one,  such  as  physicians,  nurses,  etc. 

Insects  and  animals  may  be  the  sources,  the  vehicles,  and 
the  intermediate  hosts  of  infection. 


196  PREVENTION  OF  INFECTIOUS  DISEASES 

Animal  sources  of  infection  serve  in  glanders,  anthrax,  and 
other  infectious  animal  diseases,  in  favus,  scabies,  etc.,  or 
through  bites,  as  in  rabies,  plague,  etc. 

Animal  vehicles  of  infection  may  serve  in  almost  all  infec- 
tious diseases,  the  morbific  elements  of  which  they  may 
carry  from  diseased  to  healthy  upon  their  bodies,  or  by  means 
of  the  parasites  upon  them,  such  as  lice,  fleas,  bugs,  etc. 

Insect  sources  of  infection  carry  infective  material  upon 
their  bodies,  legs,  and  wings,  and  depositing  the  same  infec- 
tive materials  upon  the  bodies  of  healthy  persons,  on  their 
mucous  membranes,  on  wounds,  in  the  food,  milk,  water,  etc. 

It  has  been  clearly  demonstrated  that  insects — ^flies, 
fleas,  lice,  bugs,  roaches,  etc. — ^may  and  do  transmit  infective 
material  from  cholera,  typhoid,  typhus,  tuberculous  and  other 
patients,  and  are  capable  of  carrying  infection  to  healthy 
persons,  either  indirectly  to  foodstuffs,  or  directly  by  means 
of  their  bites. 

That  some  insects,  notably  the  mosquito,  may  become 
the  intermediary  host  of  several  infectious  diseases  has  been 
demonstrated  in  the  case  of  malaria,  of  yellow  fever,  and 
of  elephantiasis. 

In  these  diseases  the  infective  parasite  is  sucked  up  from 
the  blood  of  a  human  being  by  the  mosquito,  and  within 
the  body  of  the  insect  the  infective  agent  undergoes  further 
development,  after  which  it  may  cause  the  disease  when 
inoculated  by  the  bite  of  the  mosquito  into  a  healthy  person. 

The  spreading  of  infection  by  food  has  also  been  demon- 
strated and  is  an  accepted  fact. 

Meat,  milk,  and  other  articles  of  food  may  become  con- 
taminated with  infective  material  containing  morbific  agents, 
and  such  food  and  food  products  may  upon  ingestion  by 
healthy  persons  cause  certain  infectious  diseases.  This  is 
the  case  especially  with  those  diseases  the  morbific  agent 
of  which  has  its  port  of  entry  in  the  digestive  tract. 

The  germs  of  typhoid,  of  cholera,  of  dysentery,  and 
probably  tuberculosis  are  those  which,  if  carried  into  the 
alimentary  canal  by  various  articles  of  food,  may  cause  those 
diseases. 


IMMUNITY,  NATURAL  AND  ARTIFICIAL         197 

That  milk  is  frequently  contaminated  with  various  morbific 
agents  has  already  been  described  in  a  previous  chapter,  and 
the  etiological  relation  of  infected  milk  to  disease  mentioned. 

Infection  may  also  be  carried  by  fruit,  vegetables,  bread, 
candy,  and  other  food  articles  which  are  used  without  cook- 
ing, and  which  may  carry  infective  material  from  the  diseased 
to  the  healthy  persons. 

The  infection  of  persons  by  infected  oysters  has  already 
been  alluded  to  in  another  chapter. 

The  soil  as  a  source  and  vehicle  of  infection  is  claimed  in 
plague,  cholera,  and  other  diseases,  but  its  direct  connection 
with  diseases,  except  through  the  means  of  infected  water,  has 
not  been  directly  demonstrated,  except  in  hookworm  disease. 

Air  as  a  vehicle  of  infection  may  serve  through  the  medium 
of  dust  floating  in  the  air,  or  through  the  droplets  which 
are  exhaled  and  expired  by  tuberculous  patients. 

The  relation  of  water  to  disease  has  been  treated  in  a 
former  chapter. 

Infection  by  Fomites. — By  fomites  are  understood  various 
articles  and  substances  in  use  by  man,  which  may  carry 
infectious  material  and  thus  serve  as  vehicles  of  infection. 
Money,  cloths,  rags,  bedding,  underwear,  books,  mail,  and 
the  thousand  and  one  other  articles  of  use  by  diseased  per- 
sons may  be  in  use  or  handled  by  sick  persons,  may  contain 
discharges  from  patients,  and  may  carry  these  from  them  to 
healthy  individuals. 

The  importance  of  fomites  has  been  greatly  overestimated, 
owing  to  the  misunderstanding  of  the  exact  nature  of  mor- 
bific agents  and  their  activity,  and  it  is  at  present  claimed 
that  fomites  have  nothing  to  do  in  the  case  of  some  diseases, 
while  their  importance  in  others  has  been  also  overrated. 

II.  PROPHYLAXIS  OP  INFECTIOUS  DISEASE;  IMMUNITY, 
NATURAL  AND  ARTIFICIAL. 

Three  conditions  for  successful  infection  are  absolutely 
needed:  (1)  Exposure  and  infection,  or  entrance  into 
the  body  of  a  certain  number  of  virulent  morbific  agents; 


198         PREVENTION  OF  INFECTIOUS  DISEASES 

(2)  favorable  conditions  for  the  development  of  infection; 

(3)  individual  susceptibility  to  infection. 

Leaving  the  first  two  conditions  for  future  discussion, 
we  shall  here  discuss  the  last  condition  for  infection  and 
its  value  in  the  prevention  of  infectious  diseases. 

Immunity. — Not  all  persons  are  equally  susceptible  to 
the  action  of  morbific  agents  and  their  products. 

The  normal  body,  animal  as  well  as  human,  possesses 
a  certain  natural  immunity,  or  resistance,  to  the  action  of 
bacteria  and  their  toxins.  This  vital  resistance  has  been 
defined  by  Sedgwick  as  "that  condition  of  the  normal  body, 
plant,  or  animal  in  which  it  is  able  to  cope  more  or  less 
successfully  with  unfavorable  influences  acting  upon  it 
from  without,  i.  e.,  from  the  environment." 

Vital  resistance  against  infectious  diseases  varies  with 
each  individual,  in  various  places  and  with  various  times  and 
under  various  conditions.  It  may  be  at  times  so  low  that  the 
individual  falls  an  easy  prey  to  the  first  exposure  to  infection, 
or  the  resistance  may  be  so  complete  against  a  certain  in- 
fectious disease  that  no  matter  how  great  the  number 
and  how  virulent  the  morbific  agents,  nor  how  favorable 
the  conditions,  the  person  remains  unscathed,  or  "immune." 

Immunity  then  is  a  state  of  relative  or  complete  resistance 
of  the  constitution  against  specific  disease. 

Between  extreme  susceptibility  and  complete  immunity 
there  are  many  degrees  of  partial  immunity,  so  that  these 
terms  "susceptibility"  and  "immunity"  are  relative  rather 
than  absolute.  The  immunity  may  differ  according  to 
time,  to  season,  to  place,  to  country,  to  race,  to  species, 
to  family,  to  age,  to  individual  health,  etc. 

To  cite  but  a  very  few  examples:  White  rats  are  com- 
pletely immune  against  diphtheria,  rabbits  and  guinea-pigs 
extremely  susceptible.  The  white  rat  is  immune  against 
anthrax,  the  house  rat  is  susceptible.  Among  races,  negroes 
show  great  immunity  to  yellow  fever  and  malaria,  Japanese 
and  Chinese  to  scarlet  fever. 

Besides  natural  immunity,  there  is  also  an  acquired  im- 
munity; this  is  notably  in  persons  who  have  recovered  from 


IMMUNITY,  NATURAL  AND  ARTIFICIAL         199 

certain  infectious  diseases.  Familiar  examples  are  small- 
pox, scarlet  fever,  yellow  fever,  also  measles,  typhoid,  etc. 
Not  all  infectious  diseases  seem  to  give  immunity  to  those 
recovering  from  them;  thus  persons  recovering  from  in- 
fluenza, pneumonia,  tuberculosis  seem  not  only  to  become 
immune,  but,  indeed,  are  more  susceptible  than  before. 
The  immunity  when  gained  may  be  complete  for  a  whole 
life,  or  may  last  only  for  a  more  or  less  short  time. 

The  degree  of  vital  resistance  and  immunity  vary,  as 
already  indicated,  with  many  factors,  and  in  individuals 
with  the  nutrition,  metabolism,  fatigue,  conditions  of  health, 
etc.;  and  one  or  more  of  these  conditions  either  increase 
or  decrease  the  natural  resistance,  which  is  therefore  spoken 
of  as  normal  or  physiological  vital  resistance,  or  increased 
physiological  resistance,  as  differentiated  from  natural  and 
from  acquired  immunity. 

Causes  of  Immunity. — As  to  the  causes  of  vital  resistance 
and  immunity  thpre  are  a  number  of  theories  and  hypoth- 
eses; the  most  important  ones  may  be  summed  up  as 
follows: 

The  body  possesses  certain  defensive  substances  against 
bacteria  and  their  products.  These  defensive  substances 
are  in  the  blood  and  in  the  body  fluids.  The  defensive 
substances  in  the  blood  and  body  fluids  have  the  power 
either  to  destroy  the  bacteria  themselves,  or  to  counteract 
and  neutralize  the  effects  of  the  bacterial  products. 

The  two  main  substances  which  act  in  a  defensive  capacity 

are  the  white  blood  corpuscles,  or  phagocytes,  which  "eat 

up,"  envelop,  and  destroy  the  bacteria,  and  the  alexins,  or 

^compound  defensive  substances  in  the  blood  plasma  and 

body  fluids. 

The  alexins  are  subdivided  into  several  substances,  each 
of  which  seems  to  have  a  special  defensive  capacity,  some 
of  these  substances  are  known  as  "the  complement,"  others 
as  "intermediary  bodies,"  "opsonins,"  "agglutinins,"  anti- 
toxins," etc. 

Opsonins  are  substances  in  the  blood  which  make  the 
bacteria  "more  tasteful"  to  the  phagocytes,  or  in  other 
words,  more  easily  destroyed. 


200  PREVENTION  OF  INFECTIOUS  DISEASES 

Opsonic  index  is  the  ratio  of  the  opsonic  influence  of  the 
blood  serum  of  sick  persons  to  the  blood  of  healthy  persons. 

Antitoxin  is  a  specific  reaction  product  of  bacterial  toxins, 
capable  of  neutralizing  the  toxin. 

Agglutinins  are  substances  in  the  blood  serum  which  are 
capable  of  agglutinizing  bacteria. 

Prophylaxis  by  Acquired  Immunity  and  Increased  Resistance. 
— In  order  to  prevent  infectious  disease  the  natural  physio- 
logical resistance  must  be  increased,  or  an  acquired  and 
artificial  immunity  produced. 

Increased  natural  physiological  resistance  is  obtained 
by  those  methods  which  react  upon  the  healthy  body,  by 
the  attention  to  the  precepts  of  personal  hygiene,  by  avoid- 
ance of  fatigue,  malnutrition,  uncleanliness,  intoxication 
and  other  harmful  influences,  and  by  attention  to  bathing, 
metabolism,  and  all  such  body  processes  which  increase 
the  natural  health  and  physiological  vital  resistance  of 
the  body. 

There  are  also  certain  therapeutic  measures,  such  as  the 
use  of  pilocarpine,  nuclein,  etc.,  which  are  known  to  increase 
vital  resistance,  although  their  practical  use  is  limited. 

Artificial  Immunity. — Artificial  immunity  is  divided  into 
active  and  passive,  according  as  to  whether  the  immunity 
is  developed  within  the  body  possessing  it,  or  is  transferred 
to  it  from  other  animals. 

Active  immunity  is  produced  by  the  following  conditions: 
(1)  Recovery  from  disease.  (2)  Inoculation  with  virulent 
living  bacteria.  (3)  Vaccination  with  attenuated  bacteria; 
(4)  with  dead  bacteria;  (5)  with  bacterial  extracts. 

Passive  immunity  is  conferred  by  antitoxins  and  serums. 

Recovery  from  Disease. — Mention  has  already  been  made 
that  recovery  from  certain  infectious  diseases  confers  a 
more  or  less  permanent  immunity.  The  immunity  is  equally 
conferred  whether  the  disease  is  of  a  virulent  type  or  is  very 
mild,  hence  the  exposure  of  healthy  persons  to  a  mild  form 
of  infectious  disease  may  become  beneficial  by  the  immunity 
conferred  by  it  against  the  more  virulent  types.  As  a 
matter  of  voluntary  prophylaxis  this  form  of  immunity  is 
not  without  its  dans'ers. 


IMMUNITY,  NATURAL  AND  ARTIFICIAL         201 

Inoculation  by  Virulent  Bacteria. — This  is  based  upon 
the  same  principles  as  the  immunity  conferred  by  recovery 
from  infectious  disease,  and  has  been  used  in  the  inoculation 
by  variola.  It  has  been  employed  also  in  cattle-plague 
by  inoculating  the  cattle  with  virulent  bacteria,  but  under 
unfavorable  conditions  to  the  bacteria  (in  cattle  plague 
into  the  tough  tissues  of  the  tail). 

Vaccination  by  Attenuated  Bacteria. — ^The  bacteria  are 
weakened  and  their  virulence  greatly  diminished  by  sub- 
jecting them  to  unfavorable  conditions,  and  then  vaccinating 
the  body  by  the  modified,  weakened,  and  attenuated  virus. 

The  modification  and  weakening  of  the  bacteria  may 
be  done  by  means  of  a  previous  growth  in  a  body  of  a  resistant 
animal,  as  in  the  case  of  vaccine  virus,  also  chicken  cholera. 
The  modification  may  also  be  accomplished  by  drying,  as 
in  the  case  of  rabies  virus,  or  by  means  of  heat,  as  in  anthrax, 
or  in  Haf kin's  first  cholera  serum;  other  unfavorable  factors, 
such  as  electricity,  light,  chemicals,  etc.,  may  also  be  used 
to  weaken  the  virulence  of  the  bacteria. 

Immunization  by  Dead  Bacteria. — Instead  of  using  for  the 
vaccines  living  bacteria,  dead  bacteria  are  used,  as  in 
Hafkin's  cholera,  in  Hafkin's  plague,  or  in  Koller's  typhoid 
virus. 

Immunization  by  Bacterial  Products. — Finally,  it  was  sought 
to  produce  artificial  immunity  by  injecting  into  the  body 
of  bacterial  products.  This  was  used  not  so  much  for  the 
purpose  of  immunization  as  for  therapeutic  purposes,  as 
in  the  case  of  tuberculin  (tuberculosis)  and  plasmin  (cholera, 
typhoid). 

Passive  Immunity. — While  active  immunity  is  produced 
by  the  persons  themselves  by  means  of  the  reaction  of  their 
body  blood  and  fluid  with  living  or  dead  bacteria  and  bac- 
terial products,  passive  immunity  is  produced  in  an  individual 
not  by  his  own  body  but  by  the  body  of  some  other  animal, 
which  has  been  artificially  immunized,  and  whose  blood 
serum  is  injected  into  the  human  being  to  be  passively 
immunized. 

Thus   if  dead  bacteria  or  bacterial   toxins   are  injected 


202         PREVENTION  OF  INFECTIOUS  DISEASES 

into  r  on- immune  horses  until  the  horses  become  highly  im- 
munized the  serum  of  these  immunized  horses  possesses 
certain  antimicrobic  and  antitoxic  properties,  which  act  as 
antibacterials  and  antitoxins  if  injected  into  the  human  body. 

The  principal  antitoxin  serums  used  are  those  of  diphtheria 
and  of  tetanus,  the  latter  as  a  prophylactic  measure,  while 
the  former  as  a  curative  as  well  as  prophylactic  procedure. 
Antitoxins  have  also  been  made  for  cholera  and  for  the 
plague. 

Diphtheria  antitoxin,  which  has  played  such  an  important 
role  in  the  enormous  reduction  of  the  mortality  from  that 
disease,  is  at  present  prepared  in  a  large  number  of  labora- 
tories, and  it  is  very  extensively  used. 

Preparation  of  Diphtheria  Antitoxin. — The  specific  diph- 
theria bacilli  are  cultivated  in  peptone  bouillon,  where  they 
produce  their  toxins.  The  bacilli  are  then  killed  by  means 
of  heat  and  the  filtered  bouillon  is  injected  into  the  blood 
of  horses,  which  at  first  react  to  the  toxins,  but  after  re- 
peated inoculations  with  stronger  toxins  are  so  immunized 
that  they  show  no  reaction,  and  their  blood  becomes  so 
rich  in  antitoxins  that  when  the  serum  is  injected  into  small 
animals  that  were  previously  inoculated  with  diphtheria 
germs,  these  animals,  instead  of  succumbing  to  the  disease, 
as  they  invariably  do  without  the  antitoxic  horse  serum, 
recover  from  diphtheria. 

III.  PROPHYLAXIS  OF  INFECTIOUS  DISEASE:  SOCIAL 
MEASURES. 

Significance. — In  view  of  the  fact  that  infectious  diseases 
affect,  as  a  rule,  a  large  number  of  people  at  one  time,  and 
that  the  spread  of  these  diseases  is  favored  by  density  of 
population,  congestion,  means  of  transportation,  commerce, 
and  other  means  of  communication,  the  prevention  of  in- 
fectious diseases  must  be  based  largely  on  social  measures 
and  public  defensive  means. 

The    social    prophylactic    measures    adopted    in    modern 
communities  to  check,  control,  and  stop  the  spread  of  infec- 
tious diseases  may  be  summarized  as  follows: 


SOCIAL  MEASURES  203 

J  1.  Study,  research,  and  popular  education. 

2.  Report,   notification,    diagnosis,    isolation,   quarantine. 

3.  Domestic  and  hospital  treatment,   nurses,  inspection. 

4.  Individual  prophylaxis. 

5.  Public  sanitary  supervision  of  food,  milk,  and  water 
supplies,  schools,  factories,  commerce,  transportation, 

1.  Research  and  Education. — Much  of  the  headway  gained 
in  modern  times  against  infectious  diseases  is  due  to  the 
brilliant  discoveries  of  the  causes  of  disease,  discoveries 
which  were  made  possible  by  the  existence  of  public  and 
private  institutions  for  study  and  research.  Scientific 
study  of  the  nature  and  causes  of  disease  is  absolutely 
necessary  for  the  prevention  of  disease,  for  one  cannot 
prevent  diseases  without  knowing  their  true  causes. 

Another  necessary  measure  for  combating  infectious 
diseases  is  the  spread  of  popular  knowledge  among  the 
masses,  for  until  the  scientific  truths  gained  in  the  laboratory 
are  common  property  of  the  mass  of  population  the  preven- 
tion of  infectious  disease  will  remain  impracticable.  Hence 
the  spread  of  popular  education  about  infectious  diseases 
is  one  of  the  most  important  and  effective  means  of  com- 
bating the  ravages  of  those  diseases.  This  has  been  well 
proved  in  the  case  of  the  modern  popular  war  against  tuber- 
culosis, which  promises  such  brilliant  results. 

2.  Notification  and  Report. — In  order  that  sanitary  authori- 
ties should  be  able  to  cope  with  infectious  disease  they  must 
first  know  of  its  existence,  hence  the  provisions  in  the  sanitary 
codes,  etc.,  for  compulsory  notification  and  report. 

The  duty  of  reporting  the  existence  of  infectious  disease 
lies  primarily  upon  the  physician  seeing  and  treating  the 
case,  but  is  also  shared  by  other  persons  coming  in  contact 
with  the  infected  patient. 

The  diseases  to  be  reported  are  those  which  are  known 
to  be  infectious  and  communicable,  although  not  all  sanitary 
authorities  and  communities  have  uniform  laws  to  the  effect. 

By  report  of  a  disease  is  meant  the  notification  to  the  health 
authorities,  and,  in  the  case  of  communicable  disease  in 
animals,  also  to  the  respective  departments  of  agriculture 


204         PREVENTION  OF  INFECTIOUS  DISEASES 

who  have  immediate  jurisdiction,  that  a  case  of  communi- 
cable disease  exists  in  a  specified  person  or  animal  at  a  given 
address. 

The  diseases  reported  according  to  the  rules  of  sanitary 
authorities  of  most  cities  are  smallpox,  scarlet  fever,  diph- 
theria, cholera,  measles,  croup,  yellow  fever,  malaria,  typhoid, 
typhus,  relapsing  fever,  pertussis,  cerebrospinal  meningitis, 
pneumonia,  tuberculosis,  erysipelas,  septicemia,  etc. 

To  be  assured  that  the  report  of  infectious  diseases  is 
correct,  certain  cities  appoint  special  diagnosticians,  who 
are  to  confirm  the  diagnosis  of  the  private  physicians,  or 
to  make  the  diagnosis,  in  case  the  suspected  patient  has 
been  reported  by  a  layman. 

Infectious  diseases  spread  rapidly  in  congested  com- 
munities, hence  the  necessity  of  isolation  of  the  infected 
persons  from  the  healthy  ones.  Such  isolation  of  infected 
persons  should  be  voluntary  wherever  the  population  is 
educated  and  is  progressive,  but  otherwise  it  must  be  com- 
pulsory, in  order  to  prevent  the  spreading  of  the  disease 
in  crowded  communities. 

The  isolation  may  be  of  the  patient  himself,  of  the  room 
where  he  lies,  or  of  the  apartment  or  house  in  which  he 
lives,  as  well  as  of  the  family  surrounding  him.  The  degree 
of  isolation  depends  much  on  the  disease  and  the  intelligence 
of  those  who  surround  the  patient.  Where  isolation  is 
absolutely  necessary  but  for  some  reasons  cannot  very 
well  be  obtained,  as,  for  instance,  in  virulent  cases  of  small- 
pox in  crowded  tenement  houses,  there  may  be  ordered 
the  compulsory  removal  of  the  patient  to  a  hospital.  The 
sanitary  authorities  of  the  community  prescribe  the  exact 
form  of  isolation,  order  the  needed  quarantine  of  the  room  or 
house,  place  the  necessary  placards,  and  perform  such  other 
preventive  acts  as  are  deemed  good  for  the  public  health. 

The  duration  of  isolation  of  patient,  etc.,  depends  on 
the  disease,  and  may  last  but  a  few  days  in  a  case  of  diphtheria 
to  a  few  months  in  a  case  of  scarlet  fever. 

3.  The  treatment  of  infectious  disease  is  either  private 
or  hospital.     There  is  no  doubt  that  for  the  public  good 


SOCIAL  MEASURES  205 

and  for  the  thorough  eradication  of  infectious  diseases, 
hospital  treatment  of  all  cases  of  infectious  diseases  would 
be  preferable,  as  best  tending  to  help  not  only  the  patient, 
but  to  prevent  the  spreading  of  the  disease  in  the  community; 
but  there  are  still  many  objections  against  compulsory 
hospital  treatment  of  all  infectious  diseases  as  a  summary 
measure,  and  it  must  be  limited  but  to  certain  few  diseases 
and  to  the  poorest  part  of  population. 

In  order  to  exercise  some  control  over  the  infectious 
diseases  treated  at  home,  sanitary  authorities  appoint  visiting 
nurses  and  inspectors.  The  medical  inspectors  do  not, 
as  a  rule,  treat  the  patients,  but  have  a  general  supervision 
over  the  case,  take  cultures,  if  requested  by  the  family 
physician,  inject  antitoxin,  or  perform  intubation,  at  the 
request  of  the  physician  treating  the  case,  also  determine 
the  time  of  termination  of  period  of  isolation  and  quarantine. 

Visiting  nurses  are  a  comparatively  new  institution,  and 
have  been  introduced  in  but  few  communities,  but  are 
destined  to  play  a  more  prominent  role  in  the  prevention 
of  infectious  diseases. 

The  nurses  visit  the  sick  at  certain  intervals,  instruct 
the  family  of  the  patient  in  the  methods  of  proper  care 
of  the  sick  one  and  of  the  various  discharges,  teach  them 
of  the  ways  to  prevent  infection  spreading  to  other  persons, 
and  generally  act  in  a  friendly  and  advisory  capacity,  which 
must  bring  very  good  results,  especially  among  the  more 
ignorant  part  of  the  population. 

4.  Individual  Prophylaxis. — ^The  individual  prophylactic 
measures  consist  in  the  care  of  the  patient;  of  the  discharges; 
of  the  proper  disinfection  of  the  food,  water,  and  other 
supplies  of  the  patient;  of  his  room,  apartment,  and  house; 
of  the  destruction  of  insects  and  other  conveyors  of  infec- 
tion, and  of  the  many  other  measures  necessary  for  the 
limiting  of  infection. 

5.  Public  Measures. — Certam  public  measures  are  neces- 
sary for  the  prevention  of  the  spread  of  infectious  diseases. 
These  measures  consist  in  the  control  of  public  food,  milk 
and  water  supplies,  in    the    prevention    of    infections    in 


206  PREVENTION  OF  INFECTIOUS  DISEASES 

schools,  factories,  by  means  of  transportation,  by  commerce, 
maritime  vessels,  interment,  etc. 

The  public  prophylactic  measures  adopted  to  lessen 
and  limit  infectious  diseases  by  means  of  public  water, 
food  and  milk  supplies,  have  already  been  discussed  in 
some  detail  in  the  chapters  upon  those  subjects. 

The  school  as  a  source  and  field  of  spread  of  infectious 
diseases  has  also  been  spoken  of,  and  the  modern  methods 
of  prevention  mentioned  as  consisting  in  a  thorough  system 
of  medical  school  supervision.  During  epidemics  it  has 
been  found  necessary  to  close  schools  for  certain  periods. 

No  less  a  prominent  factor  in  spreading  infection  is  found 
in  the  factory  and  industrial  establishments,  and  prophy- 
lactic measures  are  required  to  limit  communication  of 
disease  in  industries.  The  best  method  of  prevention  would 
be  a  proper  medical  supervision  and  control  of  all  industrial 
establishments,  with  initial  medical  examination  of  em- 
ployees, also  periodical  examination  of  all  persons  in  employ- 
ment and  isolation  of  infected  ones. 

The  supervision  of  commerce,  transportation,  means 
of  transit  by  railroads  and  steamships  is  also  necessary 
in  the  work  of  the  public  for  prevention  of  the  spread  of 
infectious  diseases.  The  measures  adopted  for  this  purpose 
are  the  supervision  and  inspection  of  railroad  and  steam- 
ships, quarantine  between  cities,  states,  and  countries  in  times 
of  epidemics,  the  inspection  and  disinfection  of  vehicles,  cars, 
baggage,  etc. 

Measures  for  supervision  of  the  interment  of  persons 
dead  from  infectious  diseases  consist  in  the  disinfection  of 
bodies,  means  of  transportation,  and  the  provisions  against 
public  funerals  in  cases  of  communicable  diseases. 

IV.   PROPHYLAXIS  OF  INFECTIOUS  DISEASE:   DESTRUC- 
TION OF  MORBIFIC  AGENTS.     DISINFECTION. 

Difficulties  of  Destruction. — It  is  evident  that  the  ideal 
means  of  prevention  of  infectious  diseases  would  be  the 
destruction  of  the  morbific  agents  which  have  been  found 


DESTRUCTION  OF  MORBIFIC  AGENTS  207 

to  be  the  cause  of  those  diseases.  The  difficulties,  how- 
ever, which  render  this  form  of  prophylaxis  unattainable 
are  (1)  that  the  morbific  agents  of  all  infectious  diseases 
are  not  as  yet  known;  (2)  that  the  known  morbific  agents 
are  microscopic,  invisible  to  the  eye  and  cannot  be  found 
without  special  and  expert  knowledge;  (3)  that  the  micro- 
scopic causative  agents  of  diseases  are  ubiquitous,  and 
found  everywhere,  not  only  upon  the  sick  persons,  but 
also  upon  the  healthy  ones,  in  the  air,  in  the  dust,  in  the 
soil,  water,  food,  milk,  clothing,  houses,  indoors  and  out- 
doors, and  everywhere,  so  that  it  is  difficult  to  find  a  place 
where  they  are  not  present;  and  (4)  finally,  the  morbific 
agents  are  not  found  free  in  nature  but  are  in  close  contact 
with  various  matter  to  which  they  cling  and  it  is  the  most 
difficult  task  to  separate  them  and  free  them  from  their 
surroundings. 

Where,  however,  the  presence  of  morbific  agents  is  sus- 
pected or  ascertained  it  is  not  very  difficult  to  destroy  them. 

Viability  of  Bacteria. — Not  all  bacteria  and  morbific 
agents  possess  the  same  viability;  there  are  certain  con- 
ditions, like  mild  heat,  moisture,  and  nutrition,  which  are 
favorable  to  their  growth  and  development,  while  other 
conditions,  like  too  low  or  too  high  temperatures,  dryness, 
absence  of  nutrition,  and  various  physical  and  chemical 
agents,  that  are  either  inhibitive  or  destructive  to  the 
bacteria. 

The  destructive  point  of  most  bacteria  differs  according 
to  the  species,  and  this  is  also  the  case  with  the  effects  of 
heat  upon  them. 

Some  bacteria  succumb  to  comparatively  mild  degrees 
of  heat  (as,  for  instance,  the  spirillum  of  cholera  at  125°  F. 
for  four  minutes),  while  others  resist  a  boiling  point  a 
long  time  before  being  killed.  This  is  especially  the  case 
with  those  bacteria  which  produce  spores,  notably  the 
tetanus  and  anthrax  bacilli. 

The  proper  means  of  destruction  of  pathogenic  bacteria 
will  vary,  therefore,  according  to  the  kind  and  species  of 
microorganism,  and  also  according  to  the  medium  in  which 


208  PREVENTION  OF  INFECTIOUS  DISEASES 

it  may  be  found,  to  the  places  where  it  may  be  lodged,  and 
to  many  other  factors. 

A  definition  of  the  various  terms  used  in  the  inhibition 
and  destruction  of  pathogenic  germs  will  be  of  benefit. 

Disinfection  is  the  absolute  destruction  of  pathogenic 
germs,  or  the  morbific  agents. 

A  disinfectant  is  an  agent  capable  of  destroying  patho- 
genic germs.    A  germicide  means  the  same. 

Sterilization  is  the  absolute  destruction  of  all  organic 
life,  whether  infective  or  not;  it  is,  therefore,  more  than 
disinfection  which  destroys  the  germs  of  infection  only. 

Fumigation  is  a  process  by  which  the  destruction  of  insects, 
as  mosquitoes  and  body  lice,  and  animals,  as  rats,  is  accom- 
plished by  the  employment  of  gaseous  agents. 

Antiseptics  are  agents  capable  of  inhibiting  pathogenic 
germs  without  totally  destroying  them;  a  disinfectant  must 
be  an  antiseptic,  but  an  antiseptic  may  not  be  a  disinfectant. 

Asepsis  is  the  absence  or  exclusion  of  bacteria. 

An  insecticide  is  an  agent  capable  of  destroying  insects; 
it  is  not  necessarily  a  disinfectant,  nor  may  a  disinfectant 
be  an  insecticide. 

A  deodorant  is  a  substance  which  neutralizes  or  destroys 
unpleasant  odors;  it  is  not  a  disinfectant. 

Disinfectants  are  divided  into  three  principal  groups — 
physical,  chemical,  and  gaseous. 

Physical  Disinfectants. — Low  temperatures  are  not  regarded 
as  disinfectants,  as  they  do  not  destroy  bacteria,  but  only 
inhibit  their  action  and  growth. 

Simlight  is  a  good  disinfectant,  provided  the  infective 
materials  and  the  germs  are  directly  exposed  to  the  rays 
of  the  sun.  The  germ-destroying  action  of  the  light  is 
thought  to  be  due  to  the  ultraviolet  rays.  Some  germs 
are  killed  within  a  very  short  time  of  exposure  to  the  direct 
rays  of  the  sun.  Tubercle  bacilli  are  killed  by  direct  sun 
rays  within  ten  to  twenty  minutes  of  exposure,  depending 
on  the  media  in  which  they  are  located.  Electric  and  other 
artificial  light  is  said  to  have  some  germicidal  action,  but 
very  slight  in  comparison  to  sun  rays. 


DESTRUCTION  OF  MORBIFIC  AGENTS  209 

Desiccation  is,  like  cold,  an  antiseptic,  not  a  germicide, 
for,  while  bacteria  must  have  moisture  as  a  condition  of  their 
life  and  growth,  desiccation  will  not  always  kill  them;  espe- 
cially is  this  the  case  with  the  spore-bearing  germs.  Koch 
proved  that  the  spore-bearing  bacteria  resist  drying  for 
indefinite  periods.  Non-spore-bearing  bacteria  lose  their 
viability  after  complete  drying. 

Heat. — Of  the  physical  disinfectants,  heat  is  the  most 
valuable,  the  most  reliable,  and  the  most  commonly  employed. 

Heat  may  be  applied  as  a  disinfectant  in  several  modes: 
By  burning,  baking,  boiling,  and  steaming. 

Burning  is  applicable  only  to  such  infected  materials  and 
objects  which  are  so  much  infected  as  to  make  any  other 
destruction  of  infective  agents  difficult  or  impossible,  or  it 
may  be  applied  to  infected  materials  which  are  of  so  little 
value  as  not  to  pay  for  the  expense  of  any  other  method. 
It  is  not  always  easy  to  destroy  certain  infected  materials 
by  burning;  at  least,  certain  infected  objects,  like  mattresses, 
etc.,  infected  with  cholera  or  typhoid  excreta,  may  need 
very  high  degree  of  heat,  possible  only  in  special  furnaces, 
for  the  total  and  absolute  destruction  of  all  germs,  and 
unless  the  objects  are  totally  consumed  and  turned  to  ashes, 
the  process  may  not  be  regarded  complete. 

Dry    Heat. — Some    spore-bearing    bacteria    are    able    to 

withstand  very  high  degrees  of  dry  heat  (140°  C).     This 

method  is  applicable  but  to  such  objects  as  are  not  injured 

or  destroyed  by  dry  heat,  such  as  metal  and  glass  and  like 

'  materials. 

Boiling. — Most  bacteria  are  killed  at  temperatures  very 
much  under  the  boiling  point  of  water,  while  boiling  for 
half  an  hour  destroys  most  spore-bearing  bacteria.  Boiling 
is,  therefore,  a  very  valuable  and  efficient  as  well  as  in- 
expensive method  of  destruction  of  infective  agents  and 
materials,  and  is  applicable  to  all  objects  which  are  not 
injured  by  the  process,  such  as  underwear,  some  kinds  of 
clothing,  textile  fabrics,  etc. 

Steam. — This  is  the  most  valuable  and  efficient  disinfecting 
method;  steam  kills  all  bacteria  at  once,  while  the  most 
14 


210  PREVENTION  OF  INFECTIOUS  DISEASES 

resisting  spores  are  destroyed  within  a  very  short  period; 
steam  is  also  very  penetrating  and  may  be  apphed  to  a  great 
many  objects  without  injuring  them.  Steam  may  be 
applied  in  a  small  way  for  domestic  disinfection:  in  con- 
venient Koch  and  Arnold  sterilizers,  as  well  as  in  a  large 
way  for  large  objects  in  institutions  and  hospitals. 

Steam  may  be  used  for  disinfecting  purposes  in  two 
forms — either  as  saturated,  streaming  steam,  or  as  super- 
heated steam  under  pressure.  While  streaming  steam 
may  be  sufficient  for  certain  objects  and  infected  materials, 
the  penetrating  qualities  of  superheated  steam  used  under 
pressure,  and  the  fact  that  such  steam  leaves  disinfected 
objects  dry,  make  such  form  of  steam  disinfection  more 
valuable  and  efficient. 

Streaming  steam  is  used  in  the  disinfection  of  objects 
by  the  popular  Arnold  disinfector,  as  well  as  by  the  Koch 
apparatus.  For  disinfection  by  steam  under  pressure  special 
apparatus,  autoclaves,  are  used,  which  are  made  of  wrought 
iron,  or  steel  pots  or  kettles,  cylindrical  in  form,  lined  with 
asbestos  and  provided  with  several  chambers  also  supplied 
with  means  to  produce  a  vacuum  in  the  steam  chamber. 

Chemical  Disinfectants. — Certain  chemicals  are  capable  of 
destroying  pathogenic  bacteria  coming  into  contact  with  them. 

The  chemicals  may  be  used  in  solid  or  liquid  form  or 
as  gases.  The  disinfectant  qualities  depend  on  the  char- 
acter of  the  chemical  constituents,  the  form  in  which  they 
are  used,  and  the  material  in  which  the  infective  agents 
and  germs  are  lodged. 

The  objections  against  chemicals  as  disinfectants  is  that 
most  of  them  must  be  used  in  very  strong  solutions,  such 
as  destroy  not  only  the  infective  agents,  but  .also  the  whole 
object  to  be  disinfected;  also  the  fact  that  chemical  dis- 
infectants must  be  thoroughly  mixed  with  infected  objects 
and  come  into  direct  contact  with  the  infective  germs,  other- 
wise their  action  is  not  destructive.  It  is  exceedingly  difficult 
to  disinfect  properly  certain  infected  objects  like  cholera 
and  typhoid  discharges  unless  the  chemicals  are  very  thor- 
oughly mixed  with  every  particle  of  the  discharges,  a  mixture 
which  is  very  difficult  to  obtain. 


DESTRUCTION  OF  MORBIFIC  AGENTS  211 

Carbolic  Acid. — A  good  antiseptic,  a  comparatively  weak 
germicide.  Carbolic  acid  is  not  applicable  to  disinfection 
of  material  infected  vdth  spore-bearing  bacteria,  as  its  action 
upon  spores  is  very  feeble,  and  it  has  been  recorded  that 
some  anthrax  spores  can  withstand  a  forty  days'  immersion 
in  a  5  per  cent,  solution  of  carbolic  acid  (Rosenau).  Non- 
spore-bearing  bacteria  are  killed  in  solution  of  carbolic  acid 
from  3  to  5  per  cent.  Carbolic  acid  has  little  penetrating 
power.  It  is  largely  used  in  solutions  from  2  to  5  per  cent, 
for  washing  floors,  walls,  wooden  surfaces,  small  objects, 
etc.,  and  its  range  of  usefulness  is  wide,  because  it  is  not 
injurious  to  most  objects. 

Ore  sols. — Of  this  group,  the  most  commonly  used  as 
disinfectants  are  creoline,  lysol,  although  others,  like  saprol, 
etc.,  may  be  employed.  The  cresols  are  more  powerful 
disinfectants  than  carbolic  acid,  and  are  used  for  about 
the  same  objects. 

Corrosive  Sublimate. — The  bichloride  of  mercury  is  a 
valuable  disinfectant,  and  is  used  in  solutions  of  from  1 
to  2000  to  1  to  500.  In  the  stronger  solutions  it  kills  germs 
rapidly,  but  because  it  unites  and  forms  insoluble  com- 
pounds with  albuminous  matter  corrosive  sublimate  loses 
much  of  its  disinfecting  property  when  used  for  infective 
agents  mixed  with  much  organic  matter.  According  to 
Rosenau,  corrosive  sublimate  kills  spores  in  solution  of 
1  to  500  after  exposure  for  one  hour;  solutions  of  1  to  1000 
destroy  non-spore-bearing  bacteria  within  a  half-hour  at  ordi- 
nary temperatures.  As  an  antiseptic,  corrosive  sublimate 
is  used  in  medical  and  surgical  practice  in  solutions  of  1  to 
2000  to  1  to  10,000. 

Lime. — In  the  form  of  chlorinated  lime,  or  of  Labarraque's 
solution,  it  is  a  good  disinfectant  for  excreta,  and  is  used 
for  disinfecting  privy  vaults,  cesspools,  cellars,  etc.  It  is 
efficient  only  when  it  is  used  freshly  prepared. 

A  number  of  other  chemicals  are  used  as  disinfectants, 
although  their  range  of  usefulness  is  limited  and  they  are 
not  commonly  so  employed.  Of  these  chemicals,  mention 
may  be  made  of  potassium  permanganate,  ferrous  sulphate, 


212  PREVENTION  OF  INFECTIOUS  DISEASES 

zinc  chloride,  copper  sulphate,  borax,  boracic  acid,  and 
a  number  of  others. 

Gaseous  Disinfectants. — Gaseous  disinfectants  are  more 
valuable  than  other  disinfectants  because  of  their  penetrating 
power  and  the  possibility  of  reaching  surfaces  and  places 
which  are  inaccessible  to  ordinary  liquid  chemicals.  Of 
the  gaseous  disinfectants  employed,  the  most  important 
one  is  formaldehyde,  which  has  lately  superseded  the  once 
very  popular  sulphur  dioxide  disinfection.  Of  the  other 
gaseous  disinfectants  sometimes  used,  are  those  of  chlorine, 
bromine,  and  hydrocyanic  acid,  but  these  have  been  dis- 
carded almost  entirely  because  of  their  very  toxic  nature 
and  their  questionable  effects  on  bacteria. 

Sulphur  dioxide  is  a  powerful  germicide  and  a  good 
surface  disinfectant;  the  disadvantages  of  sulphur  dioxide 
for  disinfection  are  (1)  that  it  is  not  very  penetrating,  (2) 
that  it  does  not  destroy  spore-bearing  bacteria,  (3)  that  it 
damages  textile  fabrics,  (4)  that  it  bleaches  vegetable  colors, 
and  (5)  that  it  injures  and  tarnishes  metals.  It  is  also 
very  poisonous  to  those  handling  it,  causes  injury  to  the 
mucous  membranes  of  the  eyes  and  nose  and  throat,  and 
leaves  a  very  disagr-^eable  odor,  clinging  to  materials  for 
a  very  long  time. 

Several  methods  of  sulphur  disinfection  are  employed:  The 
pot,  candle,  or  liquid  form,  also  by  means  of  furnace.  About 
five  pounds  of  sulphur  are  to  be  used  for  every  1000  cubic 
feet  of  space  to  be  disinfected.  Moisture  and  heat  increase 
the  penetrating  qualities  of  the  gas  and  the  value  of  dis- 
infection. An  exposure  of  twenty-four  hours  is  necessary 
for  thorough  disinfection,  and  as  the  gas  is  very  diffusible 
precautions  must  be  taken  effectively  to  close  all  windows, 
doors,  and  all  cracks,  crevices,  and  other  apertures  found 
in  the  room. 

Sulphur  disinfection  is  preferable  wherever  surface  dis- 
infection is  needed  and  where  there  are  few  articles  which 
would  be  deteriorated  by  it,  also  wherever  insecticide  action 
is  demanded. 

Formaldehyde  gas  has  greatly  superseded  sulphur  dioxide 
as  a  disinfectant.     Its  main  value  is  that,  while  it  is  a  good 


DESTRUCTION  OF  MORBIFIC  AGENTS  213 

germicide,  it  does  not  destroy  fabrics  and  injure  objects 
as  the  latter,  and  also  it  is  non-toxic.  Formaldehyde  is 
also  but  a  surface  disinfectant,  its  penetrating  qualities 
not  being  very  great.  Bacteria  are  killed  by  formaldehyde 
immediately  on  direct  exposure,  and  spores  within  an  hour. 
It  kills  dried  organisms  as  well  as  those  in  a  moist  state. 
Formaldehyde  is  not  an  insecticide.  For  domestic  dis- 
infection formaldehyde  is  generated  by  spraying  liquid 
formalin  (which  contains  40  per  cent,  of  the  gas),  or  by 
heating  paraform  pastils  or  powder,  also  by  means  of 
generators  or  lamps.  Other  methods  of  evolving  formalde- 
hyde in  disinfection  which  are  used  in  large  house  and 
hospital  disinfections  are  by  means  of  large  generators 
or  lamps,  or  in  specially  constructed  autoclaves  under 
pressure,  or  in  retorts  without  pressure. 

Disinfection  of  Rooms,  etc. —  Practical  disinfection  is  a 
process  which  needs  scientific  precision  and .  attention  to 
details.  The  disinfection  must  be  adjusted  to  the  form 
and  nature  of  infection  and  the  infected  materials  and 
objects,  each  of  which  may  need  a  different  method  of 
handling  and  disinfection. 

The  disinfection  of  rooms  and  infected  materials  will 
differ  according  to  the  disease;  various  methods  may  be 
needed  to  be  employed  after  tuberculosis,  typhoid  fever, 
yellow  fever,  diphtheria,  scarlet  fever,  etc. 

The  room  air  needs  no  disinfection,  for  whatever  germs 
may  be  found  in  dust  of  the  air  in  a  room  will  settle  upon 
the  surfaces  whenever  the  room  is  closed  and  left  undisturbed. 

The  room  walls  if  covered  with  paper  may  be  efficiently 
disinfected  by  thorough  rubbing  with  stale  bread.  Painted 
surfaces  of  walls  and  ceilings  may  be  disinfected  by  washing 
with  3  per  cent,  solution  of  carbolic  acid  or  a  1  to  500  solu- 
tion of  sublimate  of  mercury.  Floors  and  other  surfaces 
of  rooms  may  also  be  conveniently  scrubbed  with  hot  water 
and  a  solution  of  carbolic  acid  or  sublimate,  or  one  of  the 
cresols.  Carpets,  rugs,  etc.,  may  be  efficiently  disinfected 
by  a  strong  solution  of  formalin,  by  gaseous  disinfection 
with  formaldehyde,  or  may  be  taken  up  and  subjected  to 


214         PREVENTION  OF  INFECTIOUS  DISEASES 

superheated  steam  under  pressure.  Curtains,  hangings, 
etc.,  within  the  rooms  are  disinfected  with  formaldehyde, 
and  may  also  be  washed  in  boiling  water.  Wooden  bed- 
steads may  be  washed  with  a  3  per  cent,  carbolic  solution 
or  a  5  per  cent,  formalin  solution.  Bedding,  linen,  etc., 
may  be  disinfected  by  steam,  by  formalin,  and  also  by  for- 
maldehyde. 

For  the  successful  disinfection  of  rooms  with  a  gas  it 
is  necessary  to  close  all  openings,  cracks  and  crevices,  key- 
holes, etc.,  completely,  and  especially  the  crevices  about 
windows  and  doors.  This  is  done  by  means  of  cotton, 
or,  better,  by  means  of  gummed  paper  strips.  Raising 
the  temperature  of  the  room  assists  disinfection.  The 
room  is  then  closed  and  all  openings  and  crevices  sealed 
with  gummed  paper,  and  the  room  is  left  for  at  least  twenty- 
four  hours. 

Excreta,  sputum,  feces,  and  other  discharges  of  infected 
persons  must  be  gathered  and  collected  in  special  glass 
or  porcelain  vessels  and  disinfected  by  means  of  the  various 
chemical  disinfectants  like  lime,  cresols,  carbolic  acid, 
cresol,  copper  sulphate,  and  formalin.  But  whatever  dis- 
infectant is  used,  it  must  be  thoroughly  mixed  with  the  dis- 
charges, and  used  in  a  strength  sufficient  to  destroy  all  infec- 
tive material. 

V.  THE  CONTROL  OF  COMMUNICABLE  DISEASES. 

The  following  is  from  a  report  of  the  American  Public 
Health  Association  Committee  on  Standard  Regulations 
for  the  Control  of  Communicable  Diseases : 

List  of  Diseases. 

Actinomycosis.  Dysentery  (amebic). 

Acute  infectious  conjunctivitis.  Dysentery  (bacillary). 

Anchylostomiasis  (hookworm).  Favus. 

Anthrax.  German  measles. 
Cerebrospinal  meningitis  (epidemic).        Glanders. 

Chicken-pox.  Gonorrhea. 

Cholera.  Leprosy. 

Dengue.  Malaria. 

Diphtheria,  Measles. 


CONTROL  OF  COMMUNICABLE  DISEASES         215 

Mumps.  Smallpox 

Paratyphoid  fever.  Tetanus. 

Plague.  Trachoma. 

Pneumonia  (acute  lobar).  Trichinosis. 

Poliomyelitis.  Tuberculosis  (pulmonary). 

Rabies.  Tuberculosis(otherthan  pulmonary) 
Rocky    Mountain    spotted   or   tick         Typhoid  fever, 

fever.  Typhus  fever. 
Scarlet  fever.                                           ,     Whooping  cough. 

Septic  sore  throat.  Yellow  fever. 

V -*«^'«-^  •'*^^*-^'^   Actinomycosis. 

1.  Infective  Agent. — Actinomyces  bovis. 

2.  Source  of  Infection.- — The  nasal  and  bowel  discharges, 
and  the  infected  material  from  lesions  in  human  and  animal 
cases  of  the  disease.  Uncooked  meat  from  infected  animals 
may  serve  as  a  source  of  infection. 

3.  Mode  of  Transmission. — By  contact  with  the  discharges 
or  with  articles  freshly  soiled  with  the  discharges  from  animal 
or  human  cases. 

4.  Incubation  Period. — Unknown. 

5.  Period  of  Communicability . — As  long  as  open  lesions 
remain,  as  proved  by  the  presence  of  the  infective  agent  on 
microscopic  or  cultural  tests. 

6.  Methods  of  Control: 

(A)    The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms,  con- 
firmed by  microscopic  examination  of  discharges  from  the 
lesions. 

2.  Isolation — None,  provided  the  patient  is  under  adequate 
medical  supervision. 

3.  Immunization — ^None. 

4.  Quarantine — ^None. 

5.  Concurrent  disinfection — Of  discharges  from  lesions  and 
articles  soiled  therewith. 

6.  Terminal  disinfection — By  thorough  cleaning. 
(J5)   General  Measures: 

1.  Inspection  of  meat,  with  condemnation  of  carcasses,  or 
infected  parts  of  carcasses,  of  infected  animals. 

2.  Destruction  of  known  animal  sources  of  infection. 


216  PREVENTION  OF  INFECTIOUS   DISEASES 

Acute  Infectious  Conjunctivitis  (Not  Including  Trachoma).    , 

(This  title  to  replace  the  terms  gonorrheal  ophthalmia, 
ophthalmia  neonatorum,  and  babies'  sore  eyes.) 

1.  Infectious  Agent. — The  gonococcus  or  some  members 
of  a  group  of  pyogenic  organisms,  including  the  hemo- 
globinophilic  bacilli. 

2.  Source  of  Infection.- — Discharges  from  conjunctivae,  or 
adnexa,  or  genital  mucous  membranes  of  infected  persons. 

3 .  Modes  of  Transmission. — Contact  with  an  infected  person 
or  with  articles  freshly  soiled  with  discharges  of  such  person. 

4.  Incubation  Period. — Irregular,  but  usually  thirty-six  to 
forty-eight  hours. 

5.  Period  of  Communicability. — During  the  course  of  the 
disease  and  until  the  discharges  from  the  infected  mucous 
membranes  have  ceased. 

6.  Methods  of  Control: 

(A)  The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms,  con- 
firmed where  possible  by  bacteriological  examination. 

2.  Isolation — None,  provided  the  patient  is  under  ade- 
quate medical  supervision. 

S.  Immunization — ^None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection^ — Disinfection  of  conjunctival 
discharges  and  articles  soiled  therewith. 

6.  Terminal  disinfection — Thorough  cleansing. 

( B)  General  Measures: 

1.  Enforcement  of  regulations  forbidding  the  use  of 
common  towels  ajid  toilet  articles.  Education  as  to  personal 
cleanliness. 

2.  Use  of  silver  nitrate  or  some  similar  solution  in  the  eyes 
of  the  newborn. 


Anchylostomiasis  (Hookworm). 

1.  Infectious  Agent. — Anchylostoma  (Necatoramericanus). 

2.  Source  of  Infection. — Feces  of  infected  persons.     Infec- 


CONTROL  OF  COMMUNICABLE  DISEASES         217 

tion  generally  takes  place  through  the  skin,  occasionally  by 
the  mouth. 

3.  Mode  of  Transmission. — The  larval  forms  pierce  the  skin, 
usually  of  the  foot,  and  passing  through  the  lymphatics  to 
the  vena  cava  and  the  right  heart,  thence  in  the  blood  stream 
to  the  lungs,  they  pierce  the  capillary  walls  and  pass  into  the 
alveoli.  Then  they  pass  up  the  bronchi  and  trachea  to  the 
throat,  whence  they  are  swallowed  and  finally  lodge  in  the 
small  intestine.  Also  by  drinking  water  containing  larvae,  by 
eating  soiled  food,  by  hand  to  mouth  transmission  of  the  eggs 
or  larvse  from  objects  soiled  with  infected  discharges. 

4.  Incubation  Period, — Seven  to  ten  weeks. 

5.  Period  of  CommiinicabiUty.- — As  long  as  the  parasite  or 
its  ova  are  found  in  the  bowel  discharges  of  an  infected 
individual.  Contaminated  soil  remains  infective  for  five 
months  in  the  absence  of  freezing. 

6.  ■  Methods  of  Control: 

(A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Microscopic  examination 
of  bowel  discharges. 

2.  Isolation — None. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection — Sanitary  disposal  of  bow^el 
discharges. 

6.  Terminal  disinfection — None. 

7.  Treatment — Appropriate  treatment  of  infected  indi- 
vidual to  rid  the  intestinal  canal  of  the  parasite  and  its  ova. 

{B)   General  Measures: 

1.  Education  as  to  dangers  of  soil  pollution. 

2.  Prevention  of  soil  pollution  by  installation  of  sanitary 
disposal  systems  for  human  discharges. 

3.  Personal  prophylaxis  by  cleanliness  and  the  wearing  of 
shoes. 


218         PREVENTION  OF  INFECTIOUS  DISEASES 

Anthrax. 

1.  Infectious  Agent. — Bacillus  anthracis. 

2.  Source  of  Infection. — Hair,  hides,  flesh,  and  feces  of 
infected  animals. 

3.  Mode  of  Transmission. — Inoculation  as  by  accidental 
wound  or  scratch,  inhalation  of  spores  of  the  infectious  agent, 
and  ingestion  of  insufficiently  cooked  infected  meat. 

4.  Incubation  Period. — ^Within  seven  days. 

5.  Period  of  Communicahility. — During  the  febrile  stage 
of  the  disease  and  until  lesions  have  ceased  discharging. 
Infected  hair  and  hides  of  infected  animals  may  communicate 
the  disease  for  many  months  after  slaughter  of  the  animal, 
and  after  curing  of  hide,  fur,  or  hair,  unless  disinfected. 

6.  Methods  of  Control: 

(A)  The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms,  con- 
firmed by  bacteriological  examination. 

2.  Isolation  of  the  infected  individual  ilntil  the  lesions 
have  healed. 

3.  Immunization — ^None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection  of  the  discharges  from  lesions 
and  articles  soiled  therewith. 

6.  Terminal  disinfection — Thorough  cleaning. 

(B)  General  Measures: 

1.  Animals  ill  with  a  disease  presumably  anthrax  should 
be  placed  immediately  in  the  care  of  a  veterinary  surgeon. 
Proved  animal  cases  of  the  disease  should  be  killed  promptly 
and  the  carcasses  destroyed,  preferably  by  fire. 

2.  Isolation  of  all  animals  affected  with  the  disease. 

3.  Immunization  of  exposed  animals  under  direction  of 
Federal  or  State  Department  of  Agriculture. 

4.  Postmortem  examinations  should  be  made  only  by  a 
veterinary  surgeon,  or  in  the  presence  of  one. 

5.  Milk  from  an  infected  animal  should  not  be  used  during 
the  febrile  period. 

6.  Control  and  disinfection  of  effluents  and  trade  wastes 


CONTROL  OF  COMMUNICABLE  DISEASES         219 

and  of  areas  of  land  polluted  by  such  effluents  and  wastes 
from  factories  or  premises,  where  spore-infected  hides  or 
other  infected  hide  and  hair  products  are  known  to  have 
been  worked  up  into  manufactured  articles. 

7.  A  physician  should  be  constantly  employed  by  every 
company  handling  raw  hides,  or  such  companies  should 
operate  under  the  direct  supervision  of  a  medical  representa- 
tive of  the  health  department. 

8.  Every  employee  handling  raw  hides,  hair,  or  bristles 
who  has  an  abrasion  of  the  skin  should  immediately  report 
to  a  physician. 

9.  Special  instruction  should  be  given  to  all  employees 
handling  raw  hides  in  regard  to  the  necessity  of  personal 
cleanliness. 

10.  Tanneries  and  woolen  mills  should  be  provided  with 
proper  ventilating  apparatus  so  that  dust  can  be  promptly 
removed. 

11.  Disiafection  of  hair,  wool,  and  bristles  of  animals 
originating  in  known  infected  centers  before  they  are  used 
or  assorted. 

12.  The  sale  of  hides  from  an  animal  infected  with  anthrax 
should  be  prohibited.  A  violation  of  this  regulation  should 
be  immediately  reported  to  the  State  commissioner  of  agri- 
culture, by  telegram,  stating  the  time,  place,  and  piu^chaser 
to  whom  the  hide  was  sold.  The  report  should  also  be  sent 
to  the  person  purchasing  the  hide.  Carcasses  should  be  dis- 
posed of  under  the  supervision  of  the  State  department  of 
agriculture.  The  inspection  and  disinfection  of  imported 
hides  are  under  the  supervision  of  the  United  States  Bureau 
of  Animal  Industry.  In  the  event  that  infection  is  intro- 
duced the  State  agricultural  authorities  have  jurisdiction 
over  infected  animals  and  the  local  or  State  health  authori- 
ties have  jurisdiction  over  infected  persons. 

Cerebrospinal  Meningitis. 

1.  Infective  Agent. — Diplococcus  intracellularis  (the  menin- 
gococcus). 


220  PREVENTION  OF  INFECTIOUS  DISEASES 

2.  Source  of  Infection. — Discharges  from  the  nose  and 
mouth  of  infected  persons.  Clinically  recovered  cases,  and 
healthy  persons  who  have  never  had  the  disease  but  have 
been  in  contact  with  cases  of  the  disease  or  other  carriers, 
act  as  carriers  and  are  commonly  found,  especially  during 
epidemics.  Such  healthy  carriers  are  not  uncommonly  found 
independent  of  epidemic  prevalence  of  the  disease. 

3.  Mode  of  Transmission. — By  direct  contact  with  infected 
persons  and  carriers,  and  indirectly  by  contact  with  articles 
freshly  soiled  with  the  nasal  and  mouth  discharges  of  such 
persons. 

4.  Incubation  Period. — ^Two  to  ten  days,  commonly  seven. 
Occasionally  for  longer  periods  when  a  person  is  a  carrier 
for  a  time  before  developing  the  disease. 

5.  Period  of  Communicahility. — During  the  clinical  course 
of  the  disease  and  until  the  specific  organism  is  no  longer 
present  in  the  nasal  and  mouth  discharges  of  the  patient. 
The  same  applies  to  healthy  carriers  so  far  as  affects  persist- 
ence of  infectious  discharges. 

6.  Methods  of  Control: 

(A)  The  infected  individiial  and  his  enmronment: 

1.  Recognition  of  the  disease — Clinical  s^Tnptoms,  con- 
firmed by  the  microscopic  and  bacteriological  examination 
of  the  spinal  fluid,  and  by  bacteriological  examination  of 
nasal  and  pharjoigeal  secretions. 

2.  Isolation  of  infected  persons  and  carriers  until  the  naso- 
pharynx is  free  from  the  infecting  organism,  or,  at  the 
earliest,  until  one  week  after  the  fever  has  subsided. 

3.  Immunization  may  prove  of  value.  Immunization  by 
the  use  of  vaccines  still  in  the  experimental  stage. 

4.  Quarantine— None. 

5.  Concurrent  disinfection  of  discharges  from  the  nose  and 
mouth  and  of  articles  soiled  therewith. 

6.  Terminal  disinfection — Cleaning. 

(B)  General  Measures: 

1.  Search  for  carriers  among  families  and  associates  of 
recognized  cases  by  bacteriological  examination  of  posterior 
nares  of  all  contacts. 


CONTROL  OF  COMMUNICABLE  DISEASES         221 

2.  Education  as  to  personal  cleanliness  and  necessity  of 
avoiding  contact  and  droplet  infection. 

3.  Prevention  of  overcrowding  such  as  is  common  in  living 
quarters,  transportation  conveyances,  working  places,  and 
places  of  public  assembly  in  the  civilian  population,  and  in 
inadequately  ventilated  closed  quarters  in  barracks,  camps, 
and  ships  among  military  units. 


Chicken-pox. 

1.  Infectious  Agent. — Unknown. 

2.  Source  of  Infection. — -The  infectious  agent  is  presumably 
present  in  the  lesions  of  the  skin  and  of  the  mucous  mem- 
branes; the  latter  appearing  early  and  rupturing  as  soon  as 
they  appear,  render  the  disease  communicable  early,  that  is, 
before  the  exanthem  is  in  evidence. 

3.  Mode  of  Transmission. — Directly  from  person  to  person; 
indirectly  through  articles  freshly  soiled  by  discharges  from 
an  infected  individual. 

4.  Incubation  Period. — Two  to  three  weeks. 

5.  Period  of  Communicability.  —  Until  the  primary  scabs 
have  disappeared  from  the  mucous  membranes  and  the  skin. 

6.  Methods  of  Control: 

(A)    The  infected  indimdual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms.  The 
differential  diagnosis  of  this  disease  from  smallpox  is  impor- 
tant, especially  in  people  over  fifteen  years  of  age. 

2.  Isolation — Exclusion  of  patient  from  school,  and  pre- 
vention of  contact  with  non-immune  persons. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection  of  articles  soiled  by  discharges 
from  lesions. 

6.  Terminal  disinfection — Thorough  cleaning. 
(jB)   General  Measures:  None. 


222         PREVENTION  OF  INFECTIOUS  DISEASES 

Cholera. 

1.  Infectious  Agent. — ^Vibrio  cholerse. 

2.  Source  of  Infection. — Bowel  discharges  and  vomitus  of 
infected  persons,  and  feces  of  convalescent  or  healthy  carriers. 
Ten  per  cent,  of  contacts  may  be  found  to  be  carriers. 

3.  Mode  of  Transmission. — By  food  and  water  polluted  by 
infectious  agent;  by  contact  with  infected  persons,  carriers, 
or  articles  freshly  soiled  by  their  discharges;  by  flies. 

4.  Incubation  Period.— One  to  five,  usually  three,  days, 
occasionally  longer  if  the  healthy  carrier  stage,  before  develop- 
ment of  symptoms,  is  included. 

5.  Period  of  Communicability. — Usually  seven  to  fourteen 
days  or  longer  and  until  the  infectious  organism  is  absent 
from  the  bowel  discharges. 

6.  Methods  of  Control: 

(A)  The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms,  con- 
firmed by  bacteriological  examination. 

2.  Isolation  of  patient  in  hospital  or  screened  room. 

3.  Immunization  by  vaccination  may  be  of  value. 

4.  Quarantine — Contacts  for  five  days  from  last  exposure, 
or  longer  if  stools  are  found  to  contain  the  cholera  vibrio. 

5.  Concurrent  disinfection — Prompt  and  thorough  disin- 
fection of  the  stools  and  vomited  matter.  Articles  used  by 
and  in  connection  with  the  patient  must  be  disinfected  before 
removal  from  the  room.  Food  left  by  the  patient  should  be 
burned. 

6.  Terminal  disinfection — Bodies  of  those  dying  from 
cholera  should  be  cremated  if  practicable,  or,  otherwise, 
wrapped  in  a  sheet  wet  with  disinfectant  solution  and  placed 
in  water-tight  caskets.  The  room  in  which  a  sick  patient 
was  isolated  should  be  thoroughly  cleaned  and  disinfected. 

( B)  General  Measures: 

1.  Rigid  personal  prophylaxis  of  attendants  by  scrupulous 
cleanliness,  disinfection  of  hands  each  time  after  handling 
patient  or  touching  articles  contaminated  by  dejecta,  the 
avoidance  of  eating  or  drinking  anything  in  the  room  of  the 


CONTROL  OF  COMMUNICABLE  DISEASES         223 

patient,  and  the  prohibition  of  those  attendant  on  the  sick 
from  entering  the  kitchen. 

2.  The  bacteriological  examination  of  the  stools  of  all 
contacts  to  determine  carriers.    Isolation  of  carriers. 

3.  Water  should  be  boiled,  if  used  for  drinking  or  toilet 
purposes,  or  if  used  in  washing  dishes  or  food  containers, 
unless  the  water  supply  is  adequately  protected  against  con- 
tamination or  is  so  treated,  as  by  chlorination,  that  the 
cholera  vibrio  can  not  survive  in  it. 

4.  Careful  supervision  of  food  and  drink.  Where  cholera 
is  prevalent,  only  cooked  foods  should  be  used.  Food  and 
drink  after  cooking  or  boiling  should  be  protected  against 
contamination,  as  by  flies  and  human  handling. 

(C)  Epidemic  Measures: 

Inspection  service  for  early  detection  and  isolation  of  cases; 
examination  of  persons  exposed  in  infected  centers  for  detec- 
tion of  carriers,  with  isolation  or  control  of  carriers;  disinfec- 
tion of  rooms  occupied  by  the  sick,  and  the  detention,  in 
suitable  camps  for  five  days,  of  those  desirous  of  leaving  for 
another  locality.  Those  so  detained  should  be  examined  for 
detection  of  carriers. 

Dengue. 

1.  Infectious  Agent. — Unknown. 

2.  Source  of  Infection. — The  blood  of  infected  persons. 

3.  Mode  of  Transmission. — By  the  bite  of  infected  mos- 
quitoes, probably  Aedes  calopus  (perhaps  also  Culex  fatigans) . 

4.  Incubation  Period. — Four  to  five  days. 

5.  Period  of  Communicahility . — During  the  febrile  stage  of 
the  disease. 

6.  Methods  of  Control: 

{A)    The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms. 

2.  Isolation — ^The  patient  must  be  kept  in  a  screened  room. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection — None. 


224  PREVENTION  OF  INFECTIOUS  DISEASES 

6.  Terminal  disinfection — None,  Upon  termination  of 
the  case,  fumigation  of  the  room  and  house,  to  destroy 
mosquitoes. 

(J?)   General  Measures: 

Measures  directed  toward  elimination  of  mosquitoes. 
Screening  of  rooms. 

Diphtheria. 

1.  Infectious  Agent. — Bacillus  diphtherise  (theKlebs-Loeffler 
bacillus) . 

2.  Source  of  Infection. — Discharges  from  diphtheritic  lesions 
of  nose,  throat,  conjunctiva,  vagina,  and  wound  surfaces. 
Secretions  from  the  nose  and  throat  of  carriers  of  the  bacillus. 

3.  Mode  of  Transmission. — Directly  by  personal  contact, 
indirectly  by  articles  freshly  soiled  with  discharges,  or  through 
infected  milk  or  milk  products. 

4.  Incubation  Period. — Usually  two  to  five  days,  occasion- 
ally longer  if  a  healthy  carrier  stage  precedes  the  develop- 
ment of  clinical  symptoms. 

5.  Period  of  Communicability. — Until  virulent  bacilli  have 
disappeared  from  the  secretions  and  the  lesions.  The  per- 
sistence of  the  bacilli  after  the  lesions  have  healed  is  variable. 
In  fully  three-quarters  of  the  cases  they  disappear  within 
two  weeks.  In  95  per  cent,  of  cases,  the  bacilli  disappear  in 
four  weeks.  In  exceptional  cases  virulent  bacilli  remain  in 
the  throat  and  discharges  for  from  two  to  six  months. 

6.  Methods  of  Control: 

(A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — By  clinical  symptoms  with 
confirmation  by  bacteriological  examination  of  discharges. 

2.  Isolation — Until  two  cultures  from  the  throat  and  two 
from  the  nose,  taken  not  less  than  twenty-four  hours  apart, 
fail  to  show  the  presence  of  diphtheria  bacilli.  Isolation  may 
be  terminated  if  persistent  diphtheria  bacilli  prove  avirulent. 
Where  termination  by  culture  is  impracticable  cases  may  be 
terminated  with  fair  safety  as  a  rule  sixteen  days  after  onset 
of  the  disease. 

3.  Immunization — Exposed  susceptibles  to  be  promptly 


CONTROL  OF  COMMUNICABLE  DISEASES         225 

immunized  by  antitoxin.  (By  susceptibles  is  meant  such 
individuals  as  are  found  to  be  non-immune  by  the  Schick  test, 
i.  e.,  those  who  give  a  positive  ceaction.) 

4.  Quarantine — All  exposed  persons  until  shown  by  bac- 
teriological examination  not  to  be  carriers. 

5.  Concurrent  disinfection  of  all  articles  which  have  been 
in  contact  with  the  patient  and  all  articles  soiled  by  dis- 
charges from  the  patient. 

6.  Terminal  disinfection — At  the  end  of  the  illness,  thor- 
ough airing  and  sunning  of  the  sick  room,  with  cleaning  or 
renovation. 

{B)   General  Measures: 

1.  Pasteurization   of  milk   supply. 

2.  Application  of  the  Schick  test  to  all  contacts,  and 
immunization  of  all  susceptibles. 

3.  Application  of  the  Schick  test  to  all  children. 

4.  Immunization  by  toxin-antitoxin  inoculation  of  all 
susceptibles. 

5.  Determination  of  presence  or  absence  of  carriers  among 
contacts,  and,  so  far  as  practicable,  in  the  community  at 
large. 

Dysentery  (Amebic). 

1.  Infectious  Agent. — Amebic  histolytica. 

2.  Source  of  Infection. — The  bowel  discharges  of  infected 
persons. 

3.  Mode  of  Transmission. — By  drinking  contaminated  water, 
and  by  eating  infected  foods,  and  by  hand  to  mouth  transfer 
of  infected  material;  from  objects  soiled  with  discharges  of 
an  infected  individual,  or  of  a  carrier;  by  flies. 

4.  Incubation  Period. — Unknown. 

5.  Period  of  Communicability. — During  course  of  disease 
and  until  repeated  microscopic  examination  of  stools  shows 
absence  of  Ameba  histolytica. 

6.  Methods  of  Control: 

(A)   The  infected  individual  and  his  environment: 
1.  Recognition  of  the  disease — Clinical  symptoms,  con- 
firmed by  microscopic  examination  of  stools. 

15 


226  PREVENTION  OF  INFECTIOUS  DISEASES 

2.  Isolation — None. 

3.  Immunization — None. 

4.  Quarantine — ^None. 

5.  Concurrent  disinfection  of  the  bowel  discharges. 

6.  Terminal  disinfection — Cleaning. 
(B)   General  Measures: 

1.  Boil  drinkmg  water  unless  the  supply  is  known  to  be 
free  from  contamination. 

2.  Water  supply  should  be  protected  against  contamina- 
tion and  supervision  should  be  exercised  over  all  foods  eaten 
raw. 

Dysentery  (Bacillary). 

1.  Infectious  Ageni. — Bacillus  dysenterise. 

2.  Source  of  Infection. — The  bowel  discharges  of  infected 
persons. 

3 .'  Mode  of  Transmission. — ^By  drinking  contaminated  water, 
and  by  eating  infected  foods ;  and  by  hand-to-mouth  transfer 
of  infected  material;  from  objects  soiled  with  discharges  of 
an  infected  individual  or  of  a  carrier;  by  flies. 

4.  Incubation  Period. — Two  to  seven  days. 

5.  Period  of  Communicahility . — During  the  febrile  period 
of  the  disease  and  until  the  organism  is  absent  from  the 
bowel  discharges. 

6.  Methods  of  Control: 

{A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  s^mptoms^  con- 
firmed by  serological  and  bacteriological  tests. 

2.  Isolation — Infected  individuals  during  the  communi- 
cable period  of  the  disease. 

3.  Immunization — ^^'accines  give  considerable  immunity. 
Ch\'ing  to  severe  reactions  their  use  is  not  uni^'ersal,  nor 
should  it  be  made  compulsory  except  under  extreme  emer- 
gency. 

4.  Quarantine — None. 

5.  Concurrent  disinfection — Bowel  discharges. 

6.  Terminal  disinfection — Cleaning. 


CONTROL  OF  COMMUNICABLE  DISEASES         227 

(B)   General  Measures: 

1.  Rigid  personal  prophylaxis  of  attendants  upon  infected 
persons. 

2.  No  milk  or  food  for  human  consumption  should  be  sold 
from  a  place  occupied  by  a  patient  unless  the  persons  engaged 
therein  occupy  quarters  separate  from  the  house  where  the 
patient  is  sick,  and  all  utensils  used  are  cleaned  and  kept  in  a 
separate  building,  and  under  a  permit  from  the  health  officer. 

3.  All  attendants  upon  persons  affected  with  this  disease 
should  be  prohibited  from  having  anything  to  do  with  the 
handling  of  food. 

4.  Necessary  precautions  against  flies. 

Favus. 

1.  Infectious  Agent. — Achorion  schoenleinii. 

2.  Source  of  Infection. — Lesions  of  skin,  particularly  on 
scalp. 

3.  Mode  of  Transmission. — Direct  contact  with  patient, 
and  indirectly  through  toilet  articles. 

4.  Incubation  Period. — Unknown. 

5.  Period  of  Communicability. — Until  skin  and  scalp  lesions 
are  all  healed. 

6.  Methods  of  Control: 

{A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms  con- 
firmed by  microscopic  examination  of  crusts. 

2.  Isolation — Exclusion  of  patient  from  school  and  other 
public  places  until  lesions  are  healed. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection — Toilet  articles  of  patient. 

6.  Terminal  disinfection — None. 
(5)   General  Measures: 

1.  Elimination  of  common  utensils,  such  as  hair  brushes 
and  combs. 

2.  Provision  for  adequate  and  intensive  treatment  and 
cure  of  cases  of  favus  at  hospitals  and  dispensaries,  to 
q,bbreviate  the  period  of  iiifectivity  of  the  patients. 


228  PREVENTION  OF  INFECTIOUS  DISEASES 

German  Measles. 

1.  Infectious  Agent — Unknown. 

2.  Source  of  Infection. — Secretions  of  the  mouth  and  pos- 
sibly of  the  nose. 

3.  Mode  of  Transmission. — ^By  direct  contact  with  the 
patient  or  with  articles  freshly  soiled  with  the  discharges 
from  the  nose  or  throat  of  the  patient. 

4.  Incubation  Period. — From  ten  to  twenty-one  days. 

5.  Period  of  Comnfiunicahility . — Eight  days  from  onset  of 
the  disease. 

6.  Method  of  Control: 

{A)   The  infected  indimdual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  sjTnptoms. 

2.  Isolation — Separation  of  the  patient  from  non-immune 
children,  and  exclusion  of  the  patient  from  school  and  public 
places  for  the  period  of  presumed  infectivity. 

3.  Immunization — ^None. 

4.  Quarantine — None  except  exclusion  of  non-immune 
children  from  school  and  public  gatherings,  from  the  eleventh 
to  the  twenty-second  day  from  date  of  exposure  to  a  recog- 
nized case. 

5.  Concurrent  disinfection — Discharges  from  the  nose  and 
throat  of  the  patient  and  articles  soiled  by  discharges. 

6.  Terminal  disinfection — Airing  and  cleaning. 
{B)   General  Measures:    None. 

Note. — The  reason  for  attempting  to  control  this  disease 
is  that  it  may  be  confused  with  scarlet  fever  during  its  early 
stages;  each  person  having  symptoms  of  the  disease  should 
therefore  be  placed  under  the  care  of  a  physician  and  the 
case  should  be  reported  to  the  local  department  of  health. 

Glanders. 

1.  Infectious  Agent. — Bacillus  mallei. 

2.  Source  of  Infection. — Discharges  from  open  lesions  of 
mucous  membranes,  or  of  the  skin  of  human  or  equine  cases 
of  the  disease  {i.  e.,  pus  and  mucus  from  the  nose,  throat,  and 
bowel  discharges  from  infected  man  and  horse). 


CONTROL  OF  COMMUNICABLE  DISEASES         229 

3.  Mode  of  Transmission.- — Contact  with  a  case  or  with 
articles  freshly  soiled  by  discharges  from  a  human  or  equine 
case. 

4.  Incubation  Period. — Unknown, 

5.  Period  of  Communicahility. — Until  bacilli  disappear  from 
discharges  or  until  lesions  have  healed. 

6.  Methods  of  Control: 

(A)  The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — By  specific  biological  reac- 
tions, such  as  the  complement-fixation  test,  the  mallein  test, 
the  agglutination  test,  or  by  non-specific  reactions,  such  as 
the  Straus  reaction,  if  confirmed  by  culture,  or  by  identifica- 
tion of  the  Bacillus  mallei,  or  by  autopsy  of  doubtful  cases. 

2.  Isolation — Human  case  at  home  or  hospital;  for  infected 
horses  destruction  rather  than  isolation  is  advised. 

3.  Immunization^None  of  established  value  or  generally 
accepted. 

4.  Quarantine  of  all  horses  in  an  infected  stable  until  all 
have  been  tested  by  specific  reaction,  and  the  removal  of 
infected  horses  and  terminal  disinfection  of  stable  have  been 
accomplished. 

5.  Concurrent  disinfection — Discharges  from  human  cases 
and  articles  soiled  therewith. 

6.  Terminal  disinfection — Stables  and  contents  where 
infected  horses  are  found. 

(B)  General  Measures: 

1.  The  abolition  of  the  common  drinking  trough  for  horses. 

2.  Sanitary  supervision  of  stables  and  blacksmith  shops. 

3.  Semi-annual  testing  of  all  horses  by  a  specific  reaction 
where  the  disease  is  common. 

4.  Testing  of  all  horses  offered  for  sale  where  the  disease 
is  common. 

Note. — In  this  disease,  as  in  all  infectious  or  communi- 
cable diseases  from  which  both  animals  and  humans  suffer, 
cases  occurring  in  animals  should  be  reported  to  the  Depart- 
ment of  Agriculture  and  human  cases  should  be  reported  to 
the  Department  of  Health,  reciprocal  notification  thereafter 
to  be  accomplished  through  official  interdepartment  channels. 


230  PREVENTION  OF  INFECTIOUS  DISEASES 


Gonorrhea. 

1.  Infectious  Agent. — Gonococcus. 

2.  Source  of  Infection. — Discharges  from  lesions  of  inflamed 
mucous  membranes  and  glands  of  infected  persons,  viz., 
urethral,  vaginal,  cervical,  conjunctival  mucous  membranes, 
and  Bartholin's  or  Skene's  glands  in  the  female,  and  Cowper's 
and  the  prostate  glands  in  the  male. 

3.  Mode  of  Transmission. — Byjdirect  personal  contact  with 
infected  persons,  and  indirectly  by  contact  with  articles 
freshly  soiled  with  the  discharges  of  such  persons. 

4.  Incubation  Period. — One  to  eight  days,  usually  three  to 
five  days. 

5.  Period  of  Commujiicahility.— As  long  as  the  gonococcus 
persists  in  an}'  of  the  discharges,  whether  the  infection  be  an 
old  or  a  recent  one. 

6.  Methods  of  Control: 

{A)   The  infected  indimdual  and  his  enmronment: 

1.  Recognition  of  the  disease — Clinical  sjonptoms,  con- 
firmed by  bacteriological  examination  or  serum  reaction. 

2.  Isolation — ^When  the  lesions  are  in  the  genito-urinary 
tract,  exclusion  from  sexual  contact,  and  when  the  lesions 
are  conjunctival,  exclusion  from  school  or  contact  with 
children,  as  long  as  the  discharges  contain  the  infecting 
organism. 

3.  Immunization — ^None. 

4.  Quarantine — -None. 

5.  Concurrent  disinfection — Discharges  from  lesions  and 
articles  soiled  therewith. 

6.  Terminal  disinfection — None. 
(B)   General  Measures: 

1.  Education  in  matters  of  sexual  hygiene,  particularly 
as  to  the  fact  that  continence  in  both  sexes  at  all  ages  is 
compatible  with  health  and  development. 

2.  Provision  for  accurate  and  early  diagnosis,  and  treat- 
ment in  hospitals  and  dispensaries  of  infected  persons  with 
consideration  for  privacy  of  record  and  provision  for  following 
cases  until  cured. 


CONTROL  OF  COMMUNICABLE  DISEASES         231 

3.  Repression  of  prostitution  by  use  of  police  power  and 
control  of  use  of  living  premises. 

4.  Restriction  of  sale  of  alcoholic  beverages. 

5.  Restrictions  of  advertising  of  services  or  medicines  for 
the  treatment  of  sex  diseases,  etc. 

6.  Elimination  of  common  towels  and  toilet  articles  from 
public  places. 

7.  Use  of  prophylactic  silver  solution  in  the  eyes  of  the 
newborn. 

8.  Exclusion  of  persons  in  the  communicable  stage  of  the 
disease  from  participation  in  the  preparing  and  serving  of 
food. 

9.  Personal  prophylaxis  should  be  advised  to  those  who 
expose  themselves  to  opportunity  for  infection. 

Leprosy. 

1.  Infectious  Agent. — Bacillus  leprae. 

2.  Source  of  Infection. — Discharges  from  lesions. 

3.  Mode  of  Transmission. — By  close,  intimate,  and  pro- 
longed contact  with  infected  individuals.  Flies  and  other 
insects  may  be  mechanical  carriers. 

4.  Incubation  Period. — Prolonged,  undetermined. 

5.  Period  of  Communicability. — Infectivity  exists  through- 
out the  duration  of  the  disease.  Where  good  standards  of 
personal  hygiene  prevail  this  disease  is  but  slightly  com- 
municable. 

6.  Methods  of  Control: 

(A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms,  con- 
firmed by  bacteriological  examination. 

2.  Isolation  for  life  in  national  leprosarium  when  this  is 
possible.  / 

3.  Immunization — None.  ^ 

4.  Quarantine — None. 

5.  Concurrent  disinfection — Discharges  and  articles  soiled 
with  discharges. 

6.  Terminal  disinfection — Thorough  cleansing  of  living 
premises  of  the  patient. 


232  PREVENTION  OF  INFECTIOUS  DISEASES 

(B)   General  Measures: 

1.  Lack  of  information  as  to  the  determining  factors  in  the 
spread  and  communication  of  the  disease  makes  any  but 
general  advice  in  matters  of  personal  hygiene  of  no  value. 

2.  As  a  temporary  expedient,  lepers  may  be  properly  cared 
for  in  local  hospitals,  or  if  conditions  of  the  patient  and  his 
environment  warrant,  he  may  be  allowed  to  remain  on  his 
own  premises  under  suitable  regulations. 

Malaria. 

1.  Infectious  Agent. — ^The  several  species  of  malarial 
organisms. 

2.  Source  of  Infection. — ^The  blood  of  an  infected  individual. 

3.  Mode  of  Transmission. — By  bite  of  the  infected  Ano- 
pheles mosquitoes.  The  mosquito  is  infected  by  biting  an 
individual  suffering  from  acute  or  chronic  malaria.  The 
parasite  develops  in  the  body  of  the  mosquito  for  from  ten 
to  fourteen  days,  after  which  time  the  sporozoites  appear  in 
its  salivary  glands. 

4.  Incubation  Period. — ^Varies  with  the  type  of  species  of 
infecting  organism  and  the  amount  of  infection;  usually 
fourteen  days  in  the  tertian  variety. 

5.  Peripd  of  Communicahility. — As  long  as  the  malaria 
organism  exists  in  the  blood. 

6.  Methods  of  Control: 

(A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  s^onptoms,  always 
to  be  confirmed  by  microscopic  examination  of  the  blood. 
Repeated  examinations  may  be  necessary. 

2.  Isolation — Exclusion  of  patient  from  approach  of  mos- 
quitoes, until  his  blood  is  rendered  free  from  malarial  para- 
sites by  thorough  treatment  with  quinine.  " 

3.  Immunization — None.  The  administration  of  pro- 
phylactic doses  of  quinine  should  be  insisted  upon  for  those 
constantly  exposed  to  infection  and  unable  to  protect  them- 
selves against  Anopheles  mosquitoes. 

4.  Quarantine — None. 


CONTROL  OF  COMMUNICABLE  DISEASES         233 

5.  Concurrent  disinfection — None.  Destruction  of  Ano- 
pheles mosquitoes  in  the  sick  room. 

6.  Terminal  disinfection — None.  Destruction  of  Anopheles 
mosquitoes  in  the  sick  room. 

(B)   General  Measures: 

1.  Employment  of  known  measures  for  destroying  larv£e  of 
anophelines  and  the  eradication  of  breeding  places  of  such 
mosquitoes. 

2.  Blood  examination  of  persons  living  in  infected  centers 
to  determine  the  incidence  of  infection. 

3.  Screening  sleeping  and  living  quarters;  use  of  mosquito 
nets. 

4.  Killing  mosquitoes  in  living  quarters. 

Measles. 

1.  Infectious  Agent. — A  filterable  virus. 

2.  Source  of  Infection. — Buccal  and  nasal  secretions  of  an 
infected  individual. 

3.  Mode  of  Transmission. — Directly  from  person  to  person; 
indirectly  through  articles  freshly  soiled  with  the  buccal 
and  nasal  discharges  of  an  infected  individual.  The  most 
easily  transmitted  of  all  communicable  diseases. 

4.  Incubation  Period. — Seven  to  eighteen  days;  usually 
fourteen  days. 

5.  Period  of  Communicahility.  —  During  the  period  of 
catarrhal  symptoms  and  until  the  cessation  of  abnormal 
mucous  membrane  secretions — ^minimum  period  of  seven 
days;  from  two  days  before  to  five  days  after  the  appearance 
of  the  rash. 

6.  Methods  of  Control: 

{A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms.  Special 
attention  to  rise  of  temperature.  Koplik  spots  and  catarrhal 
symptoms  in  exposed  individuals. 

2.  Isolation — During  period  of  communicahility. 

3.  Immunization — None. 

4.  Quarantine — Exclusion  of  exposed  susceptible  school 


234  PREVENTION  OF  INFECTIOUS  DISEASES 

children  and  teachers  from  school  until  fourteen  days  from 
last  exposure.  This  applies  to  exposure  in  the  household. 
Exclusion  of  exposed  susceptible  children  from  all  public 
gatherings  for  the  same  period. 

5.  Concurrent  disinfection — All  articles  soiled  with  the 
secretions  of  the  nose  and  throat. 

6.  Terminal  disinfection — Thorough  cleaning. 
(B)   General  Measures: 

1.  Daily  examination  of  exposed  children  and  of  other 
possibly  exposed  persons.  This  examination  should  include 
record  of  the  body  temperature.  A  non-immune  exposed 
individual  exhibiting  a  rise  of  temperature  of  0.5°  C.  or  more 
should  be  promptly  isolated  pending  diagnosis. 

2.  Schools  should  not  be  closed  or  classes  discontinued 
where  daily  observation  of  the  children  by  a  physician  or 
nurse  is  provided  for. 

3.  Education  as  to  special  danger  of  exposing  young 
children  to  those  exhibiting  acute  catarrhal  symptoms  of 
any  kind. 

Mumps. 

1.  Infective  Organism. — Unknown. 

2.  Source  of  Infection. — Secretions  of  the  mouth  and  possibly 
of  the  nose. 

3.  Mode  of  Transmission. — By  direct  contact  with  an 
infected  person  or  with  articles  freshly  soiled  with  the  dis- 
charges from  the  nose  or  throat  of  such  infected  person. 

4.  Incubation  Period. — ^From  four  to  twenty-five  days. 
The  most  common  period,  eighteen  days,  accepted  as  usual. 
A  period  of  twenty-one  days  is  not  uncommon. 

5.  Period  of  Communicability. — Unknown,  but  assumed 
to  persist  until  the  parotid  gland  has  returned  to  its  normal 
size. 

6.  Methods  of  Control: 

(A)   The  infected  individual  and  his  environment: 
1.  Recognition  of  the  disease — Inflammation  of  Steno's 
duct  may  be  of  assistance  in  recognizing  the  early  stage  of 


CONTROL  OF  COMMUNICABLE  DISEASES         235 

the  disease.    The  diagnosis  is  usually  made  on  swelling  of 
the  parotid  gland. 

2.  Isolation — Separation  of  the  patient  from  non-immune 
children  and  exclusion  of  the  patient  from  school  and  public 
places  for  the  period  of  presumed  infectivity.     (See  5.) 

3.  Immunization — None. 

4.  Quarantine — Limited  to  exclusion  of  non-immune  chil- 
dren from  school  and  public  gatherings  for  twenty-one  days 
after  last  exposure  to  a  recognized  case. 

5.  Concurrent  disinfection — All  articles  soiled  with  the 
discharges  from  the  nose  and  throat  of  the  patient. 

6.  Terminal  disinfection — None. 
(-B)  General  Measures:    None. 

Paratyphoid  Fever. 

1.  Infectious  Agent. — Bacillus  paratyphosus  A  or  B. 

2.  Source  of  Infection. — Bowel  discharges  and  urine  of 
infected  persons,  and  foods  contaminated  with  such  dis- 
Ciharges  of  infected  persons  or  of  healthy  carriers.  Healthy 
carriers  may  be  numerous  in  an  outbreak. 

3.  Mode  of  Transmission. — Directly  by  personal  contact ; 
indirectly  by  contact  with  articles  freshly  soiled  with  the 
discharges  of  infected  persons  or  through  milk,  water,  or 
food  contaminated  by  such  discharges. 

4.  Incubation  Period. — Four  to  ten  days;  average,  seven 
days. 

5.  Period  of  Communicahility . — From  the  appearance  of 
prodromal  symptoms,  throughout  the  illness  and  relapses, 
during  convalescence,  and  until  repeated  bacteriological 
examination  of  discharges  show  absence  of  the  infecting 
organism. 

6.  Methods  of  Control: 

{A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms,  con- 
firmed by  specific  agglutination  test,  and  by  bacteriological 
examination  of  blood,  bowel  discharges,  or  urine. 

2.  Isolation — In  fly-proof  room,  preferably  under  hospital 


236  PREVENTION  OF  INFECTIOUS  DISEASES 

conditions,  of  such  cases  as  cannot  command  adequate  sani- 
tary environment  and  nursing  care  in  their  homes. 

3.  Immunization  of  exposed  susceptibles. 

4.  Quarantine — ^None. 

5.  Concurrent  disinfection — Disinfection  of  all  bowel  and 
urinary  discharges  and  articles  soiled  with  them. 

6.  Terminal  disinfection — Cleaning. 
(jB)   General  Measures: 

1.  Purification  of  public  water  supplies. 

2.  Pasteurization  of  public  milk  supplies. 

3.  Supervision  of  other  food  supplies  and  of  food  handlers.^ 

4.  Prevention  of  fly  breeding. 

5.  Sanitary  disposal  of  human  excreta. 

6.  Extension  of  immunization  by  vaccination  as  far  as 
practicable. 

7.  Supervision  of  paratyphoid  carriers  and  their  exclusion 
from  the  handling  of  foods. 

8.  Systematic  examination  of  fecal  specimens,  from  those 
who  have  been  in  contact  with  recognized  cases,  to  detect 
carriers. 

9.  Exclusion  of  suspected  milk  supplies  pending  discovery 
of  the  person  or  other  cause  of  contamination  of  the  milk. 

10.  Exclusion  of  water  supply,  if  contaminated,  until 
adequately  treated  with  hypochlorite  or  other  efficient 
disinfectant,  or  unless  all  water  used  for  toilet,  cooking,  and 
drinking  purposes  is  boiled  before  use. 

Plague  (Bubonic,  Septicemic,  Pneumonic). 

1.  Infectious  Agent. — Bacillus  pestis. 

2.  Source  of  Infection. — Blood  of  infected  persons  and 
animals,  and  sputum  of  human  cases  of  plague  pneumonia. 

3.  Mode  of  Transmission. — Direct,  in  the  pneumonic  form. 
In  other  forms  the  disease  is  generally  transmitted  by  the 
bites  of  fleas  (Lemopsylla  cheopis  and  Ceratophyllus  fas- 
ciatus),  by  which  the  disease  is  carried  from  rats  to  man, 

1  The  human  disease  paratyphoid  fever  should  not  be  confused  with  cases 
of  food  poisoning,  or  infection  due  to  enteritidis  bacilli  of  animal  origin. 


CONTROL  OF  COMMUNICABLE  DISEASES         237 

also  by  fleas  from  other  rodents.  Accidental,  by  inoculation, 
or  by  the  bites  of  infected  animals.  Bedbugs  may  transmit 
the  infection;  flies  may  possibly  convey  the  infection. 

4.  Incubation  Period. — Commonly  from  three  to  seven  days, 
although  occasionally  prolonged  to  eight  or  even  fourteen 
days. 

5.  Period  of  Communicability. — Until  convalescence  is  well 
established,  period  undetermined. 

6.  Methods  of  Control: 

{A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms,  con- 
firmed by  bacteriological  examination  of  blood,  pus  from 
glandular  lesions,  or  sputum. 

2.  Isolation — Patient  in  hospital  if  practicable;  if  not,  in  a 
screened  room  which  is  free  from  vermin.^ 

3.  Immunization — Passive  immunization  of  known  ex- 
posed contacts;  active  immunization  of  those  who  may  be 
exposed. 

4.  Quarantine — Contacts  for  seven  days. 

5.  Concurrent  disinfection — All  discharges  and  articles 
freshly  soiled  therewith. 

6.  Terminal  disinfection — Thorough  cleaning  followed  by 
thorough  disinfection. 

(5)   General  Measures: 

1.  Extermination  of  rats  and  vermin  by  use  of  known 
methods  for  their  destruction;  destruction  of  rats  on  ships 
arriving  from  infected  ports;  examination  of  rats,  ground 
squirrels,  etc.,  in  areas  where  the  infection  persists,  for 
evidence  of  endemic  or  epidemic  prevalence  of  the  disease 
among  them. 

2.  Supervision  of  autopsies  of  all  deaths  during  epidemics. 

3.  Supervision  of  the  disposal  of  the  dead  during  epidemics, 
whether  by  burial,  transfer,  or  holding  in  vault,  whatever 
the  cause  of  death. 

4.  Cremation,  or  burial  in  quicklime,  of  those  dying  of  this 
disease. 

1  In  plague  pneumonia,  personal  prophylaxis,  to  avoid  droplet  infection' 
must  be  carried  out  by  persons  who  come  in  contact  with  the  sick.  Masks 
or  veils  of  cheese  cloth  should  be  worn  as  protective  measures. 


238  PREVENTION  OF  INFECTIOUS  DISEASES 

Pneumonia  (Acute  Lobar). 

1.  Infectious  Agent. — ^Various  pathogenic  bacteria  com- 
monly found  in  the  nose,  throat,  and  mouth,  such  as  the 
pneumococcus,  the  bacillus  of  Friedlander,  the  influenza 
bacillus,  etc. 

2.  Source  of  Infection. — Discharges  from  the  mouth  and 
nose  of  apparently  healthy  carriers,  as  well  as  of  recognized 
infected  individuals,  and  articles  freshly  soiled  with  such 
discharges. 

3.  Mode  of  Transmission. — By  direct  contact  with  an 
infected  person,  or  with  articles  freshly  soiled  with  the  dis- 
charges from  the  nose  or  throat  of,  and  possibly  from  infected 
dust  of  rooms  occupied  by,  infected  persons. 

4.  Incubation  Period. — Short,  usually  two  or  three  days. 

5.  Period  of  Communicahility. — Unknown;  presumably 
until  the  mouth  and  nasal  discharges  no  longer  carry  the  in- 
fectious agent  in  an  abundant  amount  or  in  a  virulent  form. 

6.  MetJiods  of  Control: 

(A)   The  infected  individual  and  his  environment: 

1 .  Recognition  of  the  disease — Clinical  symptoms.  Specific 
infecting  organisms  may  be  determined  by  serological  and 
bacteriological  tests  early  in  the  course  of  the  disease. 

2.  Isolation — Patient  during  clinical  course  of  the  disease. 

3.  Immunization — ^None;  vaccines  are  worthy  of  further 
careful  trial. 

4.  Concurrent  disinfection — Discharges  from  the  nose  and 
throat  of  the  patient. 

5.  Terminal  disinfection — ^Thorough  cleaning,  airing,  and 
sunning. 

{B)   General  Measures: 

In  institutions  and  camps,  when  practicable,  people  in 
large  numbers  should  not  be  congregated  closely  within 
doors.  The  general  resistance  should  be  conserved  by  good 
feeding,  fresh  air,  temperance  in  the  use  of  alcoholic  beverages 
and  other  hygienic  measures. 

Note. — ^The  early  reporting  pneumonia  is  highly  desirable 
in  view  of  its  communicahility  and  the  possibility  of  effective 
treatment  of  certain  types  with  curative  sera. 


CONTROL  OF  COMMUNICABLE  DISEASES         239 

Poliomyelitis. 

1.  Infectious  Agent. — ^Not  definitely  determined.  Believed 
to  be  a  filterable  virus. 

2.  Source  of  Infection. — ^Nose,  throat,  and  bowel  discharges 
of  infected  persons  or  articles  recently  soiled  therewith. 
Healthy  carriers  are  supposed  to  be  common. 

3.  Mode  of  Transmission. — By  direct  contact  with  an 
infected  person  or  with  a  carrier  of  the  virus,  or  indirectly 
by  contact  with  articles  freshly  soiled  with  the  nose,  throat, 
or  bowel  discharges  of  such  persons. 

4.  Incubation  Period. — From  three  to  ten  days,  commonly 
six  days. 

5.  Period  of  Communicability. — Unknown;  apparently  not 
more  than  twenty-one  days  from  the  onset  of  disease,  but 
many  precede  onset  of  clinical  symptoms  by  several  days. 

6.  Methods  of  Control: 

(A)   The  infected  individual  and  his  environment: 

1 .  Recognition  of  the  disease — Clinical  symptoms,  assisted 
by  chemical  and  microscopical  examination  of  the  spinal 
fluid. 

2.  Isolation  of  all  recognized  cases  in  screened  rooms. 

3.  Immunization — None. 

4.  Quarantine  of  exposed  children  of  the  household  and 
of  adults  of  the  household  whose  vocation  brings  them  into 
contact  with  children,  or  who  are  food  handlers,  for  fourteen 
days  from  last  exposure  to  a  recognized  case. 

5.  Concurrent  disinfection — ^Nose,  throat,  and  bowel  dis- 
charges and  articles  soiled  therewith. 

6.  Terminal  disinfection — Cleaning. 

{B)   General  Measures  during  Ejndemics: 

1.  Search  for  and  examination  of  all  sick  children  should 
be  made. 

2.  All  children  with  fever  should  be  isolated  pending 
diagnosis. 

3.  Education  in  such  technic  of  bedside  nursing  as  will 
prevent  the  distribution  of  infectious  discharges  to  others 
from  cases  isolated  at  home. 


240  PREVENTION  OF  INFECTIOUS  DISEASES 

Rabies. 

1.  Infectious  Agent. — Unknown. 

2.  Source  of  Infection. — Saliva  of  infected  animals,  chiefly 
dogs. 

3.  Mode  of  Transmission. — Inoculation  with  saliva  of 
infected  animals  through  abrasion  of  skin  or  mucous  mem- 
brane, almost  always  by  bites  or  scratches. 

4.  Incubation  Period. — Usually  two  to  six  weeks.  May  be 
prolonged  to  six  months  or  even  longer. 

5.  Period  of  Communicahility. — For  fifteen  days  in  the  dog 
(not  known  in  man)  before  the  onset  of  clinical  symptoms 
and  throughout  the  clinical  course  of  the  disease. 

6.  Methods  of  Control: 

(A)  The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms,  con- 
firmed by  the  presence  of  Negri  bodies  in  the  brain  of  an 
infected  animal,  or  by  animal  inoculations  with  material 
from  the  brain  of  such  infected  animal. 

2.  Isolation — ^None  if  patients  is  under  adequate  medical 
supervision,  and  the  immediate  attendants  are  warned  of 
possibility  of  inoculation  by  human  virus. 

3.  Immunization — Preventive  vaccination  (Pasteur  treat- 
ment) after  exposure  to  infection  by  inoculation. 

4.  Quarantine — ^None. 

5.  Concurrent  disinfection  of  saliva  of  patient  and  articles 
soiled  therewith. 

6.  Terminal  disinfection — ^Thorough  cleaning. 

(B)  General  Measures: 

1.  Muzzling  of  dogs  when  on  public  streets,  or  in  places  to 
which  the  public  has  access. 

2.  Detention  and  examination  of  dogs  suspected  of  having 
rabies. 

3.  Immediate  antirabic  treatment  of  people  bitten  by 
dogs  or  by  other  animals  suspected  or  known  to  have  rabies, 
unless  the  animal  is  proved  not  to  be  rabid  by  subsequent 
observation  or  by  microscopic  examination  of  the  brain  and 
cord. 


CONTROL  OF  COMMUNICABLE  DISEASES         241 

Rocky  Mountain  Spotted  or  Tick  Fever. 

1.  Infectious  Agent. — Unknown. 

2.  Source  of  Infection. — Blood  of  infected  animals,  and 
infected  ticks  (Dermacentor  species). 

3.  Mode  of  Transmission. — By  bites  of  infected  ticks. 

4.  Incubation  Period. — Three  to  ten  days,  usually  seven 
days. 

5.  Period  of  Communicability. — Has  not  been  definitely 
determined,  probably  during  the  febrile  stage  of  the  disease. 

6.  Methods  of  Control: 

(A)  The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — By  clinical  symptoms  of  the 
disease  in  areas  where  the  disease  is  known  to  be  endemic. 

2.  Isolation — None,  other  than  care  exercised  to  protect 
patients  from  tick  bites  when  in  endemic  areas. 

3.  Immunization — ^None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection — None.  All  ticks  on  the  patient 
should  be  destroyed. 

6.  Terminal  disinfection — None. 

(B)  General  Measures: 

1.  Personal  prophylaxis  of  persons  entering  the  infected 
zones  during  the  season  of  ticks,  by  wearing  tick-proof  clothing 
and  careful  daily  search  of  the  body  for  ticks  which  may 
have  attached  themselves. 

2.  The  destruction  of  ticks  by  clearing  and  burning  vegeta- 
tion on  the  land  in  infected  zones. 

3.  The  destruction  of  ticks  on  domestic  animals  by  dipping 
and  the  pasturing  of  sheep  on  tick-infested  areas  where  the 
disease  is  prevalent,  with  the  object  of  diminishing  the  num- 
ber of  ticks. 

4.  The  destruction  of  small  mammalian  hosts  as  ground 
squirrels,  chipmunks,  etc. 


16 


242         PREVENTION  OF  INFECTIOUS  DISEASES 

Scarlet  Fever. 

1.  Infectious  Agent. — Unknown. 

2.  Source  of  Infection.— The  belief  at  present  is  that  the 
vims  is  contained  in  the  secretions  from  the  nose  and  throat, 
in  the  blood  and  in  the  lymph  nodes,  and  that  it  is  given  off 
in  the  discharges  from  the  mouth,  the  nose,  the  ears,  and  from 
broken  do^Ti  glands  of  infected  persons. 

3.  Mode  of  Transmission. — Directly  by  personal  contact 
with  an  infected  person;  indirectly  by  articles  freshly  soiled 
with  discharges  of  an  infected  person,  or  through  con- 
taminated milk. 

4.  Incubation  Period. — ^Two  to  seven  days,  usually  three 
or  four  days.  ■      ~^ — 

5.  Period  of  Communicability. — ^Four  weeks  from  the  onset 
of  the  disease,  without  regard  to  desquamation,  and  until  all 
abnormal  discharges  have  stopped  and  all  open  sores  have 
healed. 

6.  Methods  of  Control: 

(A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — By  clinical  s;>Tnptoms. 

2.  Isolation — In  home  or  hospital,  maintained  in  each  case 
until  the  end  of  the  period  of  infectivity. 

3.  Immunization^ — None. 

4.  Quarantine — Exclusion  of  exposed  susceptible  children 
and  teachers  from  school,  and  food  handlers  from  their  work, 
until  seven  days  have  elapsed  since  last  exposure  to  a  recog- 
nized case. 

5.  Concurrent  disinfection — Of  all  articles  which  have 
been  in  contact  with  a  patient  and  all  articles  soiled  with 
discharges  of  the  patient. 

6.  Terminal  disinfection — ^Thorough  cleaning. 
(J5)   General  Measures: 

1.  Daily  examination  of  exposed  children  and  of  other 
possibly  exposed  persons  for  a  week  after  last  exposure. 

2.  Schools  should  not  be  closed  where  daily  observation  of 
the  children  by  a  physician  or  nurse  can  be  provided  for. 

3.  Education  as  to  special  danger  of  exposing  young  chil- 


CONTROL  OF  COMMUNICABLE  DISEASES         243 

dren  to  those  exhibiting  acute  catarrhal  symptoms  of  any 
kind. 

4.  Pasteurization  of  milk  supply. 

Septic  Sore  Throat. 

1.  Infectious  Agent. — Streptococcus  (hemolytic  tj^je). 

2.  Source  of  Infection. — The  human  nasopharynx,  usually 
the  tonsils,  any  case  of  acute  streptococcus  inflammation  of 
these  structures  being  a  potential  source  of  infection,  includ- 
ing the  period  of  convalescence  of  such  cases.  The  udder 
of  a  cow  infected  by  the  milker  is  an  occasional  source  of 
infection.  In  such  udders  the  physical  signs  of  mastitis  are 
usually  absent.^ 

3.  Mode  of  Transmission. — Direct  or  indirect  human  con- 
tact; consumption  of  raw  milk  from  an  infected  udder. 

4.  Incubation  Period. — One  to  three  days. 

5.  Period  of  CommmiicahHity. — In  man,  presumably  during 
the  continuance  of  clinical  s\Tnptoms;  in  the  cow,  during 
the  continuance  of  discharge  of  the  streptococci  in  the  milk, 
the  condition  in  the  udder  tending  to  a  spontaneous  subsi- 
dence. The  carrier  stage  may  follow  convalescence  and 
persist  for  some  time. 

6.  Methods  of  Control: 

(A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  sjniptoms.  Bac- 
teriological examination  of  the  lesions  or  discharges  from  the 
tonsils  and  nasophar^mx  may  be  useful. 

2.  Isolation — During  the  clinical  course  of  the  disease  and 
convalescence,  and  particularly  exclusion  of  the  patient  from 
participation  in  the  production  or  handling  of  milk  or  milk 
products. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection — Articles  soiled  with  discharges 
from  the  nose  and  throat  of  the  patient. 

6.  Terminal  disinfection — Cleaning. 

1  Mastitis  in  the  cow,  due  to  bovine  streptococci,  is  not  a  cause  of  septic 
sore  throat  in  humans  unless  a  secondary  infection  of  the  udder  by  a  human 
type  of  streptococcus  takes  place. 


244         PREVENTION  OF  INFECTIOUS  DISEASES 

(B)  General  Measures: 

1.  Exclusion  of  suspected  milk  supply  from  public  sale  or 
use,  until  pasteurized.  The  exclusion  of  the  milk  of  an 
infected  cow  or  cows  in  small  herds  is  possible  when  based 
on  bacteriological  examination  of  the  milk  of  each  cow,  and 
preferably  the  milk  from  each  quarter  of  the  udder  at  fre- 
quent intervals. 

2.  Pasteurization  of  all  milk. 

3.  Education  in  the  principles  of  personal  hygiene  and 
avoidance  of  the  use  of  common  towel,  drinking,  and  eating 
utensils. 

Smallpox. 

1.  Infectious  Agent. — Unknown. 

2.  Source  of  Infection.- — Lesions  of  the  skin  and  mucous 
membranes  of  infected  persons. 

3.  Mode  of  Transmission. — By  direct  personal  contact;  by 
articles  soiled  with  discharges  from  lesions.  The  yitus  may 
be  present  in  all  body  discharges,  including  feces  and  urine. 
It  may  be  carried  by  flies. 

4.  Incubation  Period. — ^Twelve  to  fourteen  days.  (Cases 
with  incubation  period  of  twenty-one  days  are  reported.) 

5.  Period  of  Communicahility. — From  first  symptoms  to 
disappearance  of  all  scabs  and  crusts. 

6.  Methods  of  Control: 

(A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms.  Tests 
for  immunity  may  prove  useful. 

2.  Isolation — Hospital  isolation  in  screened  wards,  free 
from  vermin,  until  the  period  of  infectivity  is  over. 

3.  Immunization- — Vaccination. 

4.  Quarantine — Segregation  of  all  exposed  persons  for 
twenty-one  days  from  date  of  last  exposure,  or  until  pro- 
tected by  vaccination. 

5.  Concurrent  disinfection  of  all  discharges  and  articles 
soiled  therewith. 

6.  Terminal  disinfection — Thorough  cleaning  and  disin- 
fection of  premises. 


CONTROL  OF  COMMUNICABLE  DISEASES         245 

(J5)   General  Measures: 

General  vaccination  in  infancy,  revaccination  of  children 
on  entering  school,  and  of  entire  population  when  the  disease 
is  prevalent. 

Note. — Adjustment  of  the  time  of  vaccination  of  infants 
to  avoid  teething  or  other  mild  and  common  indisposition, 
the  time  of  vaccination  of  children  of  the  runabout  age  and 
older  with  preference  for  the  cool  months  of  the  year,  and 
the  manner  of  vaccination  with  preference  for  the  single 
puncture  or  small  area  scratch  method  through  the  droplet 
of  virus  are  important  to  observe  in  order  to  avoid  possible 
complications  or  secondary  and  subsequent  infection  at  the 
site  of  vaccination.  Vaccination  before  the  age  of  six  months 
is  particularly  desirable. 

Syphilis. 

1.  Infectious  Agent. — Treponema  pallidum. 

2.  Source  of  Infection. — Discharges  from  the  lesions  of  the 
skin  and  mucous  membranes,  and  the  blood  of  infected  per- 
sons, and  articles  freshly  soiled  with  such  discharges  or  blood 
in  which  the  Treponema  pallidum  is  present. 

3.  Mode  of  Transmission. — By  direct  personal  contact  with 
infected  persons,  and  indirectly  by  contact  with  discharges 
from  lesions  or  with  the  blood  of  such  persons. 

4.  Incubation  Period. — About  three  weeks.  (In  rare 
instances  reported  to  have  been  as  long  as  seventy  days.) 

5.  Period  of  Communicability. — As  long  as  the  lesions  are 
open  upon  the  skin  or  mucous  membranes  and  until  the  body 
is  freed  from  the  infecting  organisms,  as  shown  by  micro- 
scopic examination  of  material  from  ulcers  and  by  serum 
reactions. 

6.  Methods  of  Control: 

(A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms,  con- 
firmed by  microscopical  examination  of  discharges  and  by 
serum  reactions. 

2.  Isolation — Exclusion   from   sexual   contact   and  from 


246         PREVENTION  OF  INFECTIOUS  DISEASES 

preparation  or  serving  of  food  during  the  early  and  active 
period  of  the  disease;  otherwise  none,  unless  the  patient  is 
unwilling  to  heed,  or  is  incapable  of  observing,  the  precau- 
tions required  by  the  medical  adviser. 

3.  Immunization — None. 

4.  Quarantine — None. 

'5.  Concurrent  disinfection  of  discharges  and  of  articles 
soiled  therewith. 
6.  Terminal  disinfection — ^None. 
(B)   General  Measures: 

1.  Education  in  matters  of  sexlial  hygiene,  particularly  as 
to  the  fact  that  continence  in  both  sexes  and  at  all  ages  is 
compatible  with  health  and  development. 

2.  Provision  for  accurate  and  early  diagnosis  and  treatment 
in  hospitals  and  dispensaries,  of  infected  persons,  with  con- 
sideration for  privacy  of  record,  and  provision  for  following 
cases  until  cured. 

3.  Repression  of  prostitution  by  use  of  the  police  power 
and  control  of  use  of  living  premises. 

4.  Restriction  of  sale  of  alcoholic  beverages. 

5.  Restriction  of  advertising  of  services  or  medicines  for 
treatment  of  sex  diseases,  etc. 

6.  Abandonment  of  the  use  of  common  towels,  cups,  and 
toilet  articles  and  eating  utensils. 

7.  Exclusion  of  persons  in  the  communicable  stage  of  the 
disease  from  participation  in  the  preparing  and  serving  of 
food. 

8.  Personal  prophylaxis  should  be  advised  to  those  who 
expose  themselves  to  opportunity  to  infection. 

Tetanus. 

1.  Infectious  Agent. — Bacillus  tetani. 

2.  Source  of  Infection. — Animal  manure,  and  soil  fertilized 
with  animal  manure,  and,  rarely,  the  discharges  from  wounds. 

3.  Mode  of  Transmission. — Inoculation,  or  wound  infection. 

4.  Incubation  Period. — Six  to  fourteen  days,  usually  nine. 

5.  Period  of  Communicahility. — Patient  not  infectious  ex- 
cept in  rare  instances  where  wound  discharges  are  infectious. 


CONTROL  OF  COMMUNICABLE  DISEASES  247 

6.  Methods  of  Control: 

(A)  The  infected  individual  and  his  enmronment: 

1.  Recognition  of  the  disease — Clinical  symptoms;  may  be 
confirmed  bacteriologically. 

2.  Isolation — ^None. 

3.  Immunization — By  antitoxin,  single  or  repeated  injec- 
tion. 

4.  Quarantine — ^None. 

5.  Concurrent  disinfection — ^None. 

6.  Terminal  disinfection — None. 

(B)  General  Measures: 

1.  Supervision  of  the  practice  of  obstetrics. 

2.  Educational  propaganda  such  as  "safety-first"  cam- 
paign, and  "safe  and  sane  Fourth  of  July"  campaign. 

3.  Prophylactic  use  of  tetanus  antitoxin  where  wounds 
have  been  acquired  in  regions  where  the  soil  is  known  to  be 
heavily  contaminated,  and  in  all  cases  where  woimds  are 
ragged  or  penetrating. 

4.  Removal  of  all  foreign  matter  as  early  as  possible  from 
all  wounds. 

5.  Supervision  of  biological  products,  especially  vaccines 
and  sera. 

Trachoma. 

1.  Infectious  Agent} — The  chief,  although  not  yet  known 
to  be  the  only,  infectious  agents  are  the  hemoglobinophilic 
bacilli,  including  the  so-called  Koch-Weeks  bacillus. 

2.  Source  of  Infection. — Secretions  and  purulent  discharges 
from  the  conjunctivae  and  adnexed  mucous  membranes  of 
the  infected  persons. 

3.  Mode  of  Transmission. — By  direct  contact  with  infected 
persons  and  indirectly  by  contact  with  articles  freshly  soiled 
with  the  infective  discharges  of  such  persons. 

4.  Incubation  Period. — Undetermined. 

5.  Period  of  Communicability. — During  the  persistence  of 

1  It  has  not  yet  been  proven  that  trachoma  is  due  to  one  specific  organism 


248         PREVENTION  OF  INFECTIOUS  DISEASES 

lesions  of  the  conjimctivse  and  of  the  adnexed  mucous  mem- 
branes or  of  discharges  from  such  lesions. 
6.  Methods  of  Control: 

(A)  The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  sjTQptoms.  Bac- 
teriological examination  of  the  conjunctival  secretions  and 
lesions  may  be  useful. 

2.  Isolation — Exclusion  of  the  patient  from  general  school 
classes. 

3.  Immunization — None. 

4.  Quarantine — ^Xone. 

5.  Concurrent  disinfection  of  discharges  and  articles  soiled 
therewith. 

6.  Terminal  disinfection — ^None. 

(B)  General  Measures: 

1.  Search  for  cases  by  examination  of  school  children,  of 
immigrants,  and  among  the  families  and  associates  of  recog- 
nized cases;  in  addition,  search  for  acute  secreting  disease  of 
conjunctivae  and  adnexed  mucous  membranes,  both  among 
school  children  and  in  their  families,  and  treatment  of  such 
cases  until  cured. 

2.  Elimination  of  common  towels  and  toilet  articles  from 
public  places. 

3.  Education  in  the  principles  of  personal  cleanliness  and 
the  necessity  of  avoiding  direct  or  indirect  transference  of 
body  discharges. 

4.  Control  of  public  dispensaries  where  communicable  eye 
diseases  are  treated. 

Trichinosis. 

1.  Infectious  Agent. — Trichinella  spiralis. 

2.  Source  of  Infection. — Uncooked  or  insufficiently  cooked 
meat  of  infected  hogs. 

3.  Mods  of  Transmission. — Consumption  of  undercooked 
infected  pork  products. 

4.  Incubation  Period. — ^^'^ariable;  usually  about  one  week. 

5.  Period  of  Communicahility. — Disease  is  not  transmitted 
bv  human  hosts. 


CONTROL  OF  COMMUNICABLE  DISEASES         249 

6.  Methods  of  Control: 

(A)  The  infected  individual  and  his  enmronment: 

1.  Recognition  of  the  disease — ^^Clinical  symptoms,  eon- 
firmed  by  microscopical  examination  of  muscle  tissue  con- 
taining trichinae. 

2.  Isolation — ^None. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection — Sanitary  disposal  of  the  feces 
of  the  patient. 

6.  Terminal  disinfection — None. 

(B)  General  Measures: 

1.  Inspection  of  pork  products  for  the  detection  of  trichi- 
nosis. 

2.  Thorough  cooking  of  all  pork  products  at  a  temperature 
of  160°  F.  or  over. 

Tuberculosis  (Pulmonary). 

1.  Infectious  Agent. — Bacillus  tuberculosis  (human).  (In 
rare  instances  the  bovine  tubercle  bacillus  has  been  proved 
to  be  the  cause  of  a  pulmonary  tuberculosis.) 

2.  Source  of  Infection. — ^The  specific  organism  present  in 
the  discharges,  or  articles  freshly  soiled  with  the  discharges 
from  any  open  tuberculous  lesions,  the  most  important  dis- 
charge being  sputum.  Of  less  importance  are  discharges 
from  the  intestinal  and  genito-urinary  tracts,  or  from  lesions 
of  the  lymphatic  glands,  bone,  and  skin. 

3.  Mode  of  Transmission. — Direct  or  indirect  contact  with 
an  infected  person  by  coughing,  sneezing,  or  other  droplet 
infection,  kissing,  common  use  of  unsterilized  food  utensils, 
pipes,  toys,  drinking  cups,  etc.,  and  possibly  by  contaminated 
flies  and  dust. 

4.  Incubation  Period. — ^Variable  and  dependent  upon  the 
type  of  the  disease. 

5.  Period  of  Communicability. — Existsaslong  asthe  specific 
organism  is  eliminated  by  the  host.  Commences  when  a 
lesion  becomes  an  open  one,  i.  e.,  discharging  tubercle  bacilli, 
and  continues  until  it  heals  or  death  occurs. 


250         PREVENTION  OF  INFECTIOUS  DISEASES 

6.  Methods  of  Control: 

(A)    The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — ^By  clinical  s^^alptoms  and 
by  thorough  physical  exammation,  confirmed  by  bacterio- 
logical examination  and  by  serological  tests. 

2.  Isolation  of  such  "open"  cases  as  do  not  observe  the 
precautions  necessary  to  prevent  the  spread  of  the  disease. 

3.  Inununization — -None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection  of  sputiun  and  articles  soiled 
with  it.  Particular  attention  should  be  paid  to  prompt  dis- 
posal or  disinfection  of  sputum  itself,  of  handkerchiefs,  cloths, 
or  paper  soiled  therewith,  and  of  eating  utensils  used  by 
the  patient. 

6.  Terminal  disinfection — Cleaning  and  renovation. 
{B)   General  Measures: 

1.  Education  of  the  public  in  regard  to  the  dangers  of 
tuberculosis  and  the  methods  of  control,  with  especial  stress 
upon  the  danger  of  exposure  and  infection  in  early  childhood. 

2.  Provision  of  dispensaries  and  visiting-nurse  service  for 
discovery  of  early  cases  and  supervision  of  home  cases. 

3.  Provision  of  hospitals  for  isolation  of  advanced  cases, 
and  sanatoria  for  the  treatment  of  early  cases. 

4.  Provision  of  open-air  schools  and  preventoria  for  pre- 
tuberculous  children. 

5.  Improvement  of  housing  conditions,  and  the  nutrition 
of  the  poor. 

6.  Ventilation,  and  elimination  of  dusts  in  industrial  estab- 
lishments and  places  of  public  assembly. 

7.  Improvement  of  habits  of  personal  hygiene  and  better- 
ment of  general  living  conditions. 

8.  Separation  of  babies  from  tuberculous  mothers  at  birth. 

Tuberculosis  (Other  than  Pulmonary). 

1.  Infectious  Agent. — Bacillus  tuberculosis  (human  and 
bovine) . 

2.  Source   of  Infection. — Discharges    from    mouth,  nose, 


CONTROL  OF  COMMUNICABLE  DISEASES         251 

bowels,  and  genito-urinary  tract  of  infected  humans;  articles 
freshly  soiled  with  such  discharges;  milk  from  tuberculous 
cattle;  rarely  the  discharging  lesion  of  bones,  joints,  and 
lymph  nodes. 

3.  Mode  of  Transmission. — By  directcontact  with  infected 
persons,  by  contaminated  food,  and  possibly  by  contact  with 
articles  freshly  soiled  with  the  discharges  of  infected  persons. 

4.  Incubation  Period. — Unknown. 

5.  Period  of  Communicahility. — Until  lesions  are  healed. 

6.  Methods  of  Control: 

{A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  s^Tuptoms  con- 
firmed by  bacteriological  and  serological  examinations. 

2.  Isolation — None. 

3.  Immunization — ^None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection — Discharges  and  articles  freshly 
soiled  with  them. 

6.  Terminal  disinfection — Cleaning. 
(5)    General  Measures: 

1.  Pasteurization  of  milk  and  inspection  of  meats. 

2.  Eradication  of  tuberculous  cows  from  milch  herds  used 
in  supplying  raw  milk. 

3.  Patients  with  open  lesions  should  be  piohibited  from 
handling  foods  which  are  consumed  raw. 

Typhoid  Fever. 

1.  Infectious  Agent. — Bacillus  t^-phosus. 

2.  Source  of  Infection. — Bowel  [discharges  and  urine  of 
infected  individuals.    Healthy  carriers  are  common. 

3.  Mods  of  Transmission. — Conveyance  of  the  specific 
organism  by  direct  or  indirect  contact  with  a  soiu"ce  of 
infection.  Among  indirect  means  of  transmission  are  con- 
taminated water,  milk,  and  shellfish.  Contaminated  flies 
have  been  common  means  of  transmission  in  epidemics. 

4.  Incubation  Period. — From  seven  to  twenty-three  days, 
averaging  ten  to  fourteen  days. 


252  PREVENTION  OF  INFECTIOUS  DISEASES 

5.  Period  of  Communicability . — From  the  appearance  of 
prodromal  symptoms,  throughout  the  illness  and  relapses 
during  convalescence,  and  until  repeated  bacteriological 
examinations  of  the  discharges  show  persistent  absence  of 
the  infecting  organism. 

6.  Methods  of  Control: 

(A)  The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms,  con- 
firmed by  specific  agglutination  test  and  bacteriological 
examination  of  blood,  bowel  discharges,  or  urine. 

2.  Isolation — In  fiy-proof  room,  preferably  under  hospital 
conditions,  of  such  cases  as  cannot  command  adequate 
sanitary  environment  and  nursing  care  in  their  homes. 

3.  Immunization — Of  susceptibles  who  are  known  to  have 
been  exposed  or  are  suspected  of  having  been  exposed. 

4.  Quarantine — ^None. 

5.  Concurrent  disinfection — Disinfection  of  all  bowel  and 
urinary  discharges  and  articles  soiled  with  them. 

6.  Terminal  disinfection — Cleaning. 

(B)  General  Measures: 

1.  Purification  of  public  water  supplies. 

2.  Pasteurization  of  public  milk  supplies. 

3.  Supervision  of  other  food  supplies,  and  of  food  handlers. 

4.  Prevention  of  fly  breeding, 

5.  Sanitary  disposal  of  human  excreta. 

6.  Extension  of  immunization  by  vaccination  as  far  as 
practicable. 

7.  Supervision  of  tj^phoid  carriers  and  their  exclusion  from 
the  handling  of  foods. 

8.  Systematic  examination  of  fecal  specimens  from  those 
who  have  been  in  contact  with  recognized  cases,  to  detect 
carriers. 

9.  Exclusion  of  suspected  milk  supplies  pending  discovery 
of  the  person  or  other  cause  of  contamination  of  the  milk. 

10.  Exclusion  of  water  supply,  if  contaminated,  until 
adequately  treated  with  hypochlorite  or  other  efficient  dis- 
infectant, or  unless  all  water  used  for  toilet,  cooking,  and 
drinking  purposes  is  boiled  before  use. 


CONTROL  OF  COMMUNICABLE  DISEASES         253 

Typhus  Fever. 

1.  Infectious  Agent.  —  Bacillus  tj^hi-exanthematici  is 
claimed  to  be  the  causative  agent;  not  yet  definitely  deter- 
mined. 

2.  Source  of  Infection. — ^The  blood  of  infected  individuals. 

3.  Mode  of  Transmission. — Infectious  agent  transmitted 
by  lice.    (Pediculus  corporis,  P.  capitis.) 

4.  Incubation  Period. — Five  to  twenty  days,  usually  twelve 
days. 

5.  Period  of  Communicahility . — Until  thirty-six  hours  have 
elapsed  after  the  temperature  reaches  normal. 

6.  Methods  of  Control: 

{A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  symptoms.  (Con- 
firmation by  bacteriological  examination  of  blood  claimed 
by  Plotz.) 

2.  Isolation — In  a  vermin-free  room.  All  attendants  should 
wear  vermin-proof  clothing. 

3.  Immunization — Claimed  to  be  practicable  by  use  of 
vaccine  (Plotz,  Olitzky,  and  Baehr).  Not  yet  generally 
accepted. 

4.  Quarantine — Exposed  susceptibles  for  twelve  days  after 
last  exposure. 

5.  Concurrent  disinfection — None. 

6.  Terminal  disinfection — Destroy  all  vermin  and  vermin 
eggs  on  body  of  patient,  if  not  already  accomplished.  Destroy 
all  vermin  and  eggs  on  clothing.  Rooms  to  be  rendered  free 
from  vermin. 

{B)   General  Measures: 

Delousing  of  persons,  clothing,  and  premises  during  epi- 
demics, or  when  they  have  come  or  have  been  brought  into 
an  uninfected  place  from  an  infected  community. 

Whooping  Cough. 

1.  Infectious  Agent. — Bacillus  pertussis  (Bordet,  Gengou). 

2.  Source  of  Infection, — Discharges  from   the   lar}Tigeal 


254         PREVENTION  OF  INFECTIOUS  DISEASES 

and  bronchial  mucous  membranes  of  infected  persons  (some- 
times also  of  infected  dogs  and  cats  which  are  known  to  be 
susceptible). 

3.  Mode  of  Transmission. — Contact  with  an  infected  person 
or  animal  or  with  articles  freshly  soiled  with  the  discharges 
of  such  person  or  animal. 

4.  Incubation  Period. — ^Within  fourteen  days. 

5.  Period  of  Coinmunicahility . — Particularly  communicable 
in  the  early  catarrhal  stages  before  the  characteristic  whoop 
makes  the  clinical  diagnosis  possible.  Communicability  prob- 
ably persists  not  longer  than  two  weeks  after  the  develop- 
ment of  the  characteristic  whoop  or  approximately  four 
weeks  after  the  onset  of  catarrhal  SATuptoms. 

6.  Methods  of  Control: 

{A)   The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease — Clinical  s;>Tnptoms,  sup- 
ported by  a  differential  leukoc}'te  count,  and  confirmed  where 
possible  by  bacteriological  exammation  of  bronchial  secre- 
tions. 

2.  Isolation — Separation  of  the  patient  from  susceptible 
children,  and  exclusion  of  the  patient  from  school  and  public 
places,  for  the  period  of  presumed  infectivity. 

3.  Immimization — Use  of  prophylactic  vaccination  recom- 
mended by  some  observers.    Not  effective  in  all  cases. 

4.  Quarantine — Limited  to  the  exclusion  of  non-immune 
children  from  school  and  public  gatherings  for  fourteen  days 
after  their  last  exposure  to  a  recognized  case. 

5.  Concurrent  disinfection — Discharges  from  the  nose  and 
throat  of  the  patient  and  articles  soiled  with  such  discharges. 

6.  Terminal  disinfection — Cleaning  of  the  premises  used 
by  the  patient. 

(jB)   General  Measures: 

Education  in  habits  of  personal  cleanliness  and  in  the 
dangers  of  association  or  contact  with  those  showing  catarrhal 
6}Tnptoms  with  cough. 


QUESTIONS  255 


Yellow  Fever. 


1.  Infectious  Agent. — Unknown. 

2.  Source  of  Injection. — The  blood  of  infected  persons. 

3.  Mode  of  Transmission. — By  the  bite  of  infected  Aedes 
calopus  mosquitoes. 

4.  Incuhation  Period. — ^Three  to  five  days,  occasionally 
six  days. 

5.  Period  of  Commimicability. — First  three  days  of  the  fever. 

6.  Methods  of  Control: 

(A)  The  infected  individual  and  his  eiwironment: 

1.  Recognition  of  the  disease — Clinical  sjTQptoms. 

2.  Isolation — Isolate  from  mosquitoes  in  a  special  hospital 
ward  or  thoroughly  screened  room.  If  necessary  the  room  or 
ward  should  be  freed  from  mosquitoes  by  fumigation.  Isola- 
tion necessary  only  for  the  first  three  days  of  the  fever. 

3.  Immunization — ^None. 

4.  Quarantine — Contacts  for  six  days. 

5.  Concurrent  disinfection — ^None. 

6.  Terminal  disinfection — None.  Upon  termination  of 
case  the  premises  should  be  rendered  free  from  mosquitoes  by 
fumigation. 

(B)  General  Measures: 

Eliminate  mosquitoes  by  rendering  breeding  impossible. 

(C)  Epidemic  Measures: 

1.  Inspection  service  for  the  detection  of  those  ill  with  the 
disease. 

2.  Fumigation  of  houses  in  which  cases  of  disease  have 
occurred,  and  of  all  adjacent  houses. 

3.  Destruction  of  Aedes  calopus  mosquitoes  by  fumigation; 
use  of  larvicides;  eradication  of  breeding  places. 

QUEvSTIONS? 

Define  the  following  terms:  constitutional,  environmental,  infectious 
diseases. 

Define  the  following  terms:  exposure,  invasion,  infection,  incubation, 
acme,  crisis,  lysis,  relapse. 

Define  bacteria,  bacUli,  cocci,  spirilla,  and  give  examples  of  each. 

Name  diseases  the  morbific  agents  of  which  are  known. 

Name  infectious  diseases  the  morbific  agents  of  which  are  unknown. 


256         PREVENTION  OF  INFECTIOUS  DISEASES 

What  action  is  produced  by  the  morbific  agent  upon  the  body? 

What  are  the  cominon  portals  of  entry  of  the  morbific  agents? 

What  are  the  modes  of  their  transmission? 

What  are  the  agents  of  dissemination? 

State  in  what  way  may  domestic  animals  and  insects  become  the  source, 
the  vehicles,  and  the  intermediate  hosts  of  infection 

What  are  the  roles  of  food,  soil,  air,  and  water  in  infection? 

What  are  fomites,  and  what  is  their  probable  role  in  infection? 

Define  immunity,  natural  and  acquired  immunity. 

Give  examples  of  each. 

Define  the  following  terms:     Toxins,   phagocytes,   alexins,  agglutinins, 
opsonins,  opsonic  index,  antitoxin. 

How  is  artificial  immunity  produced? 

Define  active  and  passive  immunity. 

How  is  diphtheria  antitoxin  produced? 

Name  the  social  measures  of  the  prophylaxis  of  infectious  diseases. 

Name  the  methods  of  destruction  of  morbific  agents. 

Name  the  physical  disinfectants  and  their  value  as  such. 

Name  the  chemical  disinfectants  and  their  action. 

Describe  the  action  of  the  principal  gaseous  disinfectants. 

How  is  formaldehyde  generated  and  how  used? 

How  are  rooms  to  be  disinfected? 

What  precautions  are  to  be  taken  in  room  disinfection? 

What  are  the  various  articles  in  rooms  disinfected? 

How  are  excreta  and  discharges  from  infected  persons  disinfected? 
■*  What  are  the  infective  agents,  sources  of  infection,  modes  of  transmission, 
probation  period,  period  of  communicability,  and  methods  of  control,  of  the 
following  diseases:  Actinomycosis,  Acute  infectious  conjunctivitis,  Anchylo- 
stomiasis  (hookworm).  Anthrax,  Cerebrospinal  meningitis  (epidemic). 
Chicken-pox,  Cholera,  Dengue,  Diphtheria,  Dysentery  (amebic),  Dysentery 
(bacillary)  Favus,  German  measles.  Glanders,  Gonorrhea,  Leprosy,  Malaria, 
Measles,  Mumps,  Paratyphoid  fever.  Plague,  Pneumonia  (acute  lobar). 
Poliomyelitis,  Rabies,  Rocky  Mountain  spotted  or  tick  fever.  Scarlet  fever. 
Septic  sore  throat,  Smallpox,  Syphilis,  Tetanus,  Trachoma,  Trichinosis, 
Tuberculosis  (pulmonary).  Tuberculosis  (other  than  pulmonary),  Typhoid 
fever,  Typhus  fever.  Whooping  cough,  Yellow  fever. 


CHAPTER  XI. 
FEDERAL  HYGIENE. 

I.  HEALTH  LEGISLATION  AND  ADMINISTRATION. 

The  functions  of  public  hygiene  are  the  prevention  of 
disease,  conservation  and  promotion  of  pubUc  and  national 
health. 

The  conservation  of  national  health  and  the  prevention 
of  diseases  cannot  be  accomplished  without  the  cooperation 
of  the  public,  of  the  general  population,  aided  by  the  super- 
vision and  control  of  the  public  legislative  representatives 
and  executive  officers. 

Health  legislation  is  absolutely  necessary  for  the  purpose 
of  public  hygiene.  It  consists  in  laws,  rules,  and  regulations 
for  the  removal  of  certain  injurious  influences,  for  the  pre- 
vention of  harmful  action,  for  the  supervision  of  public 
water,  food,  and  milk  supplies,  for  proper  urban  and 
rural  sanitation,  for  prevention  and  control  of  infectious 
diseases,  and  for  the  numerous  other  functions  intended 
for  the  conservation  and  promotion  of  national  and  public 
health. 

Health  legislation  must  be  followed  by  health  adminis- 
tration, for  laws  are  but  dead  letters  unless  enforced  by 
proper  and  competent  authorities. 

In  continental  countries  health  legislation  and  adminis- 
tration are  combined  in  a  central  health  administration, 
the  duties  of  which  are  to  supervise  the  execution  of  the 
national  uniform  sanitary  laws  and  properly  to  administer 
them  throughout  the  country. 

In  the  United  States  health  legislation  and  administra- 
tion are  not  uniform  or  centralized,  but  differ  in  various 
states  and  municipalities  and  bear  a  threefold  character — 
federal,  state,  and  municipal. 

17  (257) 


258  FEDERAL  HYGIENE 

Federal  health  legislation  and  administration  are  as  yet 

very  feebly  developed  in  the  United  States,  and  is  but  limited 

I   to  the  census,  quarantine,  and  to  the  "Food  and  Drug"  act, 

State  health  administration  differs  in  many  individual 
states,  some  states  possessing  quite  advanced  sanitary 
laws,  while  others  are  wofully  behind.  The  state  health 
legislation,  when  not  issued  for  the  guidance  of  local  com- 
munities, consists  mostly  in  creation  of  State  Boards  of 
Health,  with  advisory,  rather  than  executive,  powers,  with 
some  powers  To  examine  and  prevent  certain  nuisances, 
I  administer  and  supervise  food  and  drug  and  milk  laws, 
regulate  the  sanitation  of  water  supplies,  and  prevent  certain 
1   animal  diseases,  like  tuberculosis,  glanders,  etc. 

Municipal  hygiene  is  the  one  branch  of  public  hygiene 
which  is  the  most  highly  developed,  thanks  to  the  advanced 
standing  of  some  municipalities,  especially  those  of  the 
great  centres  of  populations. 

Municipal  health  legislation,  apart  from  the  state  public 

I  health  laws,  consists  in  the   so-called  "sanitary  codes"  of 

their  sanitary  authorities,  while  the  administration  is  usually 

,    centred  in  the  Health  Departments,  or  Boards  of  Health, 

some  of  which  are  given,  by  the  state  legislatures  and  city 

charters,  wide  and  summary  powers. 

Neither  municipal  legislation,  as  crystallized  in  the  muni- 
cipal codes,  nor  municipal  administration,  as  exemplified 
in  the  Boards  of  Health,  are  uniform  in  each  municipality, 
and  hence  there  exists  throughout  the  country  a  chaotic, 
non-uniform,  and  sometimes  contradictory  irregularity  in 
sanitary  administration  and  public  health  legislation. 

National  health  being  the  greatest  national  asset,  the 
prevention  of  national  life  waste  and  the  conservation  of 
national  health  becomes  one  of  the  most  important  national 
problems  and  duties,  and  there  is  no  reason  why  the  appall- 
ing infant  mortality,  the  unnecessarily  great  death  rate, 
and  the  loss  of  life  by  preventable  diseases  should  not  be 
a  federal  function,  and  not  left  to  the  politicians  of  various 
states  and  small  hamlets  and  towns. 

Extension  and  uniformity  of  the  registration  area  through- 


VITAL  STATISTICS  259 

out  the  United  States  and  the  creation  of  a  federal  national 
department  of  health  are  the  two  objects  at  present  agitatied 
for  by  all  advanced  representatives  of  liberal  thought  and 
by  all  sanitarians. 

The  legislative  and  administrative  functions  of  the  proposed 
Federal  Department  of  Health  would  include  all  or  some  of 
the  following  activities: 

1.  Uniform  registration,  vital  statistics,  arid  census. 

2.  Study  and  control  of  infant  mortality. 

3.  Sanitary  control  of  public  education. 

4.  Sanitary  control  of  industrial  conditions,  and  especially 
female  and  child  labor. 

5.  Urban  and  rural  sanitation — research,  study,  and 
advisory  control  of  state  and  municipal  sanitary  bodies. 

6.  Sanitary  control  of  water,  milk,  and  food  supplies. 

7.  Quarantine,  interstate  and  international. 

8.  Naval,  military,  and  tropical  hygiene. 

9.  Sanitary  control  of  interstate  commerce  and  transpor- 
tation. 

10.  Sanitary  information,  research,  study,  statistics,  and 
a  system  of  popular  sanitary  education,  through  lectures, 
exhibitions,  pamphlets,  etc. 


II.  VITAL  STATISTICS. 

Definition. — Vital  statistics  is  the  collection  and  inter- 
pretation of  the  facts  of  the  lives  of  populations. 

Methods  of  Record. — The  collection  of  facts  and  figures 
about  the  life  of  the  people  is  accomplished  (1)  by  the  census, 
which  is  a  periodical  general  enumeration  of  the  population 
and  a  collection  of  detailed  data  about  the  life  of  the  whole 
people  of  the  nation,  and  (2)  by  the  system  of  registration 
of  certain  civil  data,  such  as  births,  marriages,  and  deaths, 
and  diseases,  which  is  a  function  of  most  municipahties, 
and  is  compulsory  upon  physicians,  clergymen,  etc.,  who 
become  cognizant  of  those  facts  and  upon  whom  lies  the 
duty  to  report  same. 


260  FEDERAL  HYGIENE 

The  general  census  is  made  every  ten  years,  while  the 
system  of  registration  is  supposed  to  go  on  at  all  times. 

The  great  value  of  the  facts  and  figures  gathered  by 
both  agencies  is  self-evidjent.  Without  such  data  no  con- 
sideration of  the  condition  of  the  populations  is  possible. 
Only  by  possessing  reliable  data  of  the  life  arid  condition 
of  the  population  is  it  possible  to  judge  of  their  economic, 
financial  and  sanitary  standing,  to  compare  the  condition 
of  one  part  or  portion  of  the  country  and  population  with 
other  parts  and  portions,  to  know  the  rate  of  mortality 
and  morbidity,  to  give  due  warning  of  the  increase  of 
disease  from  one  cause,  or  in  one  locality,  and  to  find  out 
the  causes  of  the  miseries  of  one  part  of  the  population  as 
compared  with  the  prosperities  of  another. 

Registration  records  the  births,  the  marriages,  and  the 
deaths,  as  well  as  the  infectious  diseases,  the  compulsory 
notification  of  which  is  a  feature  of  almost  all  sanitary 
codes.  Unfortunately  the  registration  area  comprises  as  yet 
but  less  than  50  per  cent,  of  the  area  of  the  United  States, 
and  even  in  the  registration  area  it  is  not  uniform  and  com- 
plete in  every  place,  so  that  data  gathered  by  these  means 
is  not  so  valuable  as  it  would  be  if  there  were  a  uniform 
and  efficient  system  of  registration  throughout  the  whole 
country. 

The  census,  which,  until  now,  has  been  taken  every  decen- 
nial, gives  the  number  of  population,  the  races,  nationalities, 
the  number  of  native  and  foreign  born,  the  number  of  sick 
and  the  nature  of  the  disease,  the  deaths,  births,  and 
marriages  during  the  census  year,  the  sex,  age,  race,  the 
density  and  overcrowding,  the  school,  industrial,  and  com- 
mercial relations  and  conditions,  the  numbers  of  deaths 
and  their  causes,  and  a  number  of  other  sanitary,  economic, 
and  financial  data. 

In  the  collected  data  there  are  a  number  of  errors,  of 
commission  and  omission,  and  certain  consideration  is  given 
to  the  probable  errors  in  the  interpretation  of  the  data. 

Of  the  many  facts  sought  to  be  gained  from  the  census 
and  registration  figures  the  most  important  are  the  following: 


VITAL  STATISTICS  ,  261 

The  actual  ajid  natural  increase  in  population;  the  compara- 
tive number  of  persons  of  various  races  and  nationalities;  the 
birthrates,  the  marriage  rates,  the  death  rates,  the  morbidity 
rates,  the  duration  of  life,  the  expectation  of  life,  etc. 

The  actual  increment  of  population  is  the  difference  in  the 
number  of  people  counted  by  the  census  as  compared  with 
the  census  taken  ten  years  before. 

The  natural  increment  of  population  is  the  excess  of  births 
over  deaths. 

Birth  rate  is  calculated  by  the  number  of  births  in  a  year 
per  1000  population. 

Marriage  rates  are  also  calculated  by  the  number  of  mar- 
riages per  1000  population. 

Morbidity  rates  are  calculated  only  as  to  the  infectious 
diseases  the  notification  of  which  is  compulsory,  and  rated 
by  100,000  population. 

Death  Rates. — The  gross  death  rate  is  calculated  in  the 
same  way  as  the  births  and  marriage  rates,  as  so  many 
deaths  per  1000  population,  and  is  found  out  by  dividing 
the  number  of  all  deaths  by  the  number  of  the  whole  popula- 
tion and  multiplying  the  result  by  1000.  In  the  explanation 
of  the  deaths  the  data  given  in  the  death  certificates  are 
of  very  great  value.  The  data  gives  the  nationality  of  the 
parents,  the  sex  of  the  person,  the  age  at  which  the  person 
died,  the  character  of  house  he  died  in,  the  urban  or  rural 
location  of  death,  the  race  of  the  person,  the  disease  which 
directly  caused  the  death,  and  the  disease  which  contributed 
to  the  death,  as  well  as  the  occupation  of  the  deceased. 
All  these  data  are  necessary  for  the  proper  interpretation 
of  the  figures  and  to  the  partial  explanations  of  conditions 
bearing  influence  upon  the  death  rates  of  populations. 

Infant  mortality  rates  are  calculated  not  by  the  number 
of  infants'  deaths  per  1000  population,  but  by  the  number  of 
infants'  (under  one  year)  deaths  to  the  number  of  births 
of  that  year. 

"The  mean  age  at  death  is  the  average  age  at  which  death 
occurs  in  that  population,  and  is  indicated  by  the  total  of 
the  ages  at  death  divided  by  the  number  of  deaths." 


262  FEDERAL  HYGIENE 

The  probable  duration  of  life  "is  the  age  at  which  any 
number  of  children  born  will  be  reduced  one-half,  the 
chances  thus  being  even  that  each  will  survive  to  that  age." 

Expectation  of  life  "is  the  average  number  of  years  which 
an  individual,  at  any  given  age,  will  continue  to  live,  as 
shown  by  a  life  table." 

III.  QUARANTINE. 

"Quarantine"  is  defined  by  Surgeon-General  W.  Wyman, 
as  "  the  adoption  of  restrictive  measures  to  prevent  the 
introduction  of  diseases  from  one  country  or  one  locality 
into  another."  The  term  is  derived  from  the  French  word 
quarante,  forty,  the  number  of  days  vessels  were  detained 
in  the  first  Venetian  quarantines. 

The  necessity  of  quarantine  and  of  imposing  some  restric- 
tion upon  the  freedom  of  trade  and  commerce  between 
nations  and  countries,  especially  during  epidemics,  has 
been  referred  to  in  the  previous  chapter. 

The  modes  of  quarantine  may  be  international,  national, 
state,  and  municipal,  and  each  may  impose  certain  restric- 
tions on  incoming  people  who  arrive  by  railroad  or  ship, 
and  who  may  be  suffering  from  infectious  diseases. 

Quarantine  regulations  provide  for  the  inspection  of  vessels 
arriving  at  ports,  for  the  examination  of  the  officers,  crew, 
and  passengers,  for  the  detention  of  those  already  sick 
from  infectious  diseases  and  of  suspected  cases  in  detention 
camps,  of  disinfection  of  the  cargo  and  baggage  of  the 
vessels,  and  destruction  of  rats,  etc.,  in  the  holds  of  ships. 

Quarantine  regulations  also  prescribe  the  sanitation  of 
the  vessels,  the  cleanliness,  ventilation,  etc.,  and  other  such 
rules  as  would  tend  to  the  prevention  of  diseases  in  ships. 

Clean  bills  of  health  are  at  present  required  from  all  in- 
coming vessels,  and  are  given  by  consular  agents  and 
authorities  whose  duty  it  is  to  inspect  the  vessels  and  examine 
its  populations  for  cases  of  infectious  disease. 

Quarantine  is  logically  an  interstate  function  and  should 
be  entirely  under  the  jurisdiction  and  control  of  the  Federal 
Government. 


NAVAL  HYGIENE  263 


IV.  NAVAL  HYGIENE. 

The  function  of  naval  hygiene  is  the  prevention  of  disease 
and  preservation  and  promotion  of  the  heahh  of  the  inhabi- 
tants of  seagoing;  vessels,  whether  they  belong  to  the  nation 
or  to  private  owners. 

The  problems  of  naval  hygiene  may  be  divided  into  two 
parts — the  care  of  the  persons  or  seamen,  and  the  sanitation 
of  the  ships. 

The  sanitation  of  the  ships  consists  in  the  provision  for 
proper  space  for  the  number  of  the  crew  and  passengers, 
in  the  prevention  of  overcrowding,  in  the  provision  for  the 
proper  ventilation  of  the  ships,  the  living  and  sleeping 
quarters  of  the  crew  and  passengers,  the  lighting,  the  plumb- 
ing, wash  houses,  laundries,  cooking,  and  other  quarters, 
and  especially  the  sleeping  places  of  the  crew,  and  the 
general  provision  about  cleanliness  and  sanitary  keeping 
of  vessels,  also  their  disinfection  in  cases  of  infec- 
tion. 

Ventilation  of  Ships. — The  provision  of  fresh  air  in  holds 
of  ships  presents  a  very  important  and  often  difHcult  problem. 
The  usual  methods  of  ventilation  in  holds  and  hatchways 
by  means  of  tubes,  fixed  or  temporary,  canvas  or  metal, 
or  by  means  of  hollow  masts,  etc.,  are  not  always  satis- 
factory. Natural  ventilation  generally  is  not  a  satisfactory 
way  of  providing  air  in  ships.  The  best  methods  are  those 
of  mechanical  ventilation,  propulsion  more  preferable  than 
exhaustion. 

The  water  supply  is  another  matter  of  importance  and 
supplies  the  need  of  storage  of  pure  water  aboard  ships  or  of 
machinery  for  the  sterilization  of  sea  water. 

The  sanitary  care  of  the  crew  consists  in  the  attention  to 
all  the  objects  of  individual  hygiene,  in  a  proper  and  abun- 
dant as  well  as  variable  ration,  in  the  provision  for  plenty 
of  pure  sweet  water,  in  the  examination  of  the  crew  for 
evidences  of  disease,  in  the  insistence  upon  certain  habits 
of  cleanliness,  etc.,  in  the  provision  for  treating  of  those 


264  FEDERAL  HYGIENE 

who  become  ill,  and  in  such  other  provisions  as  would  tend 
to  promote  and  preserve  the  health  of  the  crew. 

The  prevention  of  tropical  diseases  (during  sojourns 
in  the  tropics),  the  prevention  of  occupational  diseases  as 
relating  to  stokers  and  firemen,  and  the  general  prevention 
of  all  other  diseases  are  also  an  important  part  of  naval 
hygiene. 

The  crew  of  vessels,  being  enthely  in  the  hands  of  the 
officers,  even  in  commercial  navy,  there  are  certain  laws 
prescribed  by  federal  and  other  authorities  to  guard  the 
interests  and  health  of  the  men,  so  as  to  prevent  injustice 
and  inhumanity. 

V.   MILITARY  HYGIENE. 

The  function  of  military  hygiene  is  the  prevention  of  dis- 
eases among  soldiers  and  the  preservation  and  promotion 
of  their  health. 

Whether  recruited  by  conscription,  as  in  continental 
countries,  or  by  voluntary  service,  as  in  the  United  States 
and  England,  the  soldiers,  once  they  are  recruited,  lose 
their  independence  and  ability  to  care  for  their  own  health, 
and  the  care  for  their  health,  food,  clothing,  habitations, 
occupation,  etc.,  entirely  devolves  upon  their  superiors;  hence 
military  hygiene,  while  dealing  largely  with  matters  in  the 
province  of  personal  hygiene,  is  a  part  of  public  hygiene 
either  under  state  or  federal  control. 

Selection  of  Recruits. — Only  normal,  robust  and  healthy 
persons  are  chosen  for  soldiers,  and  as  a  weak  or  sickly 
individual  may  endanger  the  life  of  the  entire  body,  great 
care  is  taken  to  reject  any  man  with  the  slightest  physio- 
logical defect. 

Age. — ^Eighteen  to  forty-five  years  are  the  minimum  and 
maximum  ages  of  recruits,  but  the  best  age  for  recruits 
seems  to  be  between  twenty-one  and  thirty-five.  In  the 
World  War  men  were  drafted  from  eighteen  to  forty-five,  but 
the  use  of  boys  under  twenty  and  men  over  thirty-five  was 
mostly  limited  to  selected  services  which  did  not  require 
too  strenuous  tasks. 


MILITARY  HYGIENE  265 

Height. — ^The  minimum  height  is  5  feet  4  inches,  the 
maximum  is,  for  cavalry,  5  feet  10  inches,  and  for  other 
branches  according  to  weight.  Very  tall  men  do  not  seem 
to  have  the  endurance  and  other  qualities  necessary  for 
soldiers;  the  same  may  be  said  of  men  under  5  feet  2  inches 
in  height.  The  above  requirements  have  been  somewhat 
modified  by  Surgeon-General  Gorgas  for  recruits  to  the 
American  Army  in  the  World  War.  The  relation  of  height 
and  weight  remains  about  the  same. 

Weight. — For  cavalry  service  there  is  no  minimum  for 
weight,  provided  otherwise  fit,  while  the  maximum  for 
cavalry  is  165  pounds.  Otherwise  the  minimum  and 
maximum  weights  are  128  and  190,  though  sometimes  excep- 
tions are  made  in  accepting  otherwise  fit  recruits,  weighing  not 
less  than  1 20  pounds .  The  physiological  relation  between  height 
and  weight  is  two  pounds  for  every  inch  for  persons  5  feet 
7  inches  tall,  and  7  pounds  for  every  additional  inch  above. 

Chest  Capacity. — ^This  is  a  valuable  index  of  the  normal 
strength  of  the  recruit.  It  is  judged  by  measurement  of 
circumference  and  by  the  extent  of  the  chest  mobility. 

The  measurements  are  made  by  tape-measure  applied 
somewhat  above  the  points  of  the  shoulder-blades  behind, 
and  just  below  the  nipple  in  front.  The  chest  circum- 
ference is  taken  at  extreme  expiration  and  extreme  inspira- 
tion; the  difference  between  the  two  constitutes  the  chest 
mobility,  which  must  not  be  less  than  two  inches.  The 
following  table  of  chest  proportion  is  official : 


Height. 

Weight. 

Chest  at  expiration. 

Mobility. 

Inches. 

Pounds. 

Inches. 

Inches. 

64 

128 

32 

2 

65 

130 

32 

2 

66 

132 

32i 

2 

67 

134 

33 

2 

68 

141 

33i 

2i 

69 

148 

33i 

2i 

70 

155 

34 

2i 

71 

162 

34* 

.     2 

72 

169 

34| 

3 

The  grounds  for  rejection  are  as  follows:     Defective  devel- 
opment and  non-conformity  to  age,  height,  weight,  and  chest 


266  FEDERAL  HYGIENE 

capacity  to  above  standards,  defective  vision,  defective 
hearing,  defective  teeth,  intermittent  pulse,  weakness  and 
immobiHty  of  joints,  sensitive  testicles,  varicose  veins,  flat- 
foot,  inflamed  bunions  and  hammer  toe,  and  evidences  of 
any  diseases,  constitutional. 

Food. — The  importance  of  proper  food  for  the  soldier 
has  been  aptly  characterized  in  the  famous  saying,  "Ad 
army  travels  on  its  belly."  The  food  must  be  sufficient 
to  support  life,  but  must  also  be  prepared  so  that  there  be 
variety,  abundance  and  tastefulness.  The  rations  consist 
in  "allowance  for  the  sustenance  for  one  person  for  one 
day,  and  consists  of  the  meat,  bread,  vegetables,  coffee  and 
sugar,  the  seasoning,  and  the  soap  and  candle  components." 
The  ration  varies  somewhat  in  camp  and  for  field  or  march 
(emergency  ration). 

There  are  a  number  and  variety  of  so-called  concentrated 
rations,  in  which  it  is  sought  to  combine  several  foods  in. 
a  very  concentrated  form  and  in  small  volume,  so  as  to 
easily  carry  several  days'  rations  weighing  comparatively 
very  little;  none  of  these  rations,  however,  are  capable  of 
sustaining  life  for  very  long  periods,  and  are  used  only  for 
emergencies,  forced  marches,  et3.  Men  in  the  United  States 
Army  were  allowed  a  daily  ration  of  about  3300  calories, 
with  meat  about  twice  a  day. 

Water. — ^A  soldier  needs  from  6  to  8  pints  of  water  a  day 
for  drinking  and  cooking  when  marching,  about  5  gallons 
a  day  while  camping,  and  10  gallons  a  day  in  permanent 
camps.  This  is  exclusive  of  baths  and  sewage  disposal 
needs;  horses  need  from  6  to  10  gallons  per  day.  The 
supply  of  pure  water  for  the  soldiers  is  one  of  the  most 
important  duties  of  the  commissariat,  and  a  previous  thor- 
ough sanitary  inspection  of  the  sources  of  the  water  supply 
and  a  chemical  examination  of  the  supply  is  absolutely  neces- 
sary. Wherever  the  water  supply  is  at  all  suspicious  it  should 
be  used  Only  when  boiled,  or  there  should  be  carried  with 
the  commissariat  wagons  portable  filters.  In  the  United 
States  Army  water  is  very  often  purified  by  utilization  of 
chlorine,  a  mixture  of  calcium  hypochlorite  and  sodium 


MILITARY  HYGIENE  267 

carbonate  is  put  up  in  sealed  glass  tubes.  These  tubes  are 
broken  and  the  contents  are  stirred  into  the  water,  which  is 
allowed  to  stand  twenty  minutes  before  use.  One  part  of 
the  chemical  is  sufficient  to  purify  one  million  parts  of  the 
water.  The  chlorine  method  is  also  used  by  means  of  canvas 
bags  used  as  canteens,  in  which  bags  the  dried  calcium  hypo- 
chlorite is  introduced,  rendering  it  safe  for  drinking  in  about 
fifteen  minutes.  A  number  of  filters  are  also  used  for  the 
purpose  of  purification. 

Sewerage  and  Disposal  of  Excreta. — The  disposal  of  liquid 
and  solid  excreta  of  camps  and  barracks  is  of  paramount 
importance,  in  view  of  the  frequent  raging  of  typhoid  fever 
among  soldiers  and  the  difficulty  of.  providing  proper  means 
of  prevention  of  the  contamination  of  the  water  supply. 

Every  temporary  as  well  as  permanent  camp  should  be 
accompanied  by  a  competent  sanitary  officer,  who  should 
take  charge  of  the  planning  and  executing  of  the  proper 
provisions  for  the  disposal  of  the  m^ine  and  excreta  of  the 
soldiers,  as  well  as  of  the  proper  disposal  of  other  waste 
matters.  Such  sanitary  provisions  should  be  placed  at 
some  distance  from  the  camp  and  in  such  location  that 
it  would  not  endanger  the  water  supply.  In  temporary 
camps,  iron  pails  or  receptacles  may  be  allowed  to  be  placed 
at  a  distance  from  the  camps,  disinfected  with  proper 
solutions,  and  frequently  emptied  or  cremated  under  the 
supervision  of  proper  authorities.  In  permanent  or  semi- 
permanent camps  a  system  of  sewerage  may  be  devised 
with  plumbing  pipes  and  fixtures,  differing  but  little  from 
an  ordinary  system  of  house  plumbmg.  In  view  of  the 
great  importance  of  this  subject  in  the  prevention  of  disease 
and  preservation  of  health,  the  disposal  of  waste  and  excre- 
mentitious  matter  should  be  in  charge  not  only  of  proper 
sanitary  officers,  but  there  must  be  instituted  a  system 
of  sanitary  police  to  insure  compliance  with  the  sanitary 
rules.  A  large  number  of  latrines,  incinerators  and  other 
devices  have  been  introduced  by  the  United  States  Army  for 
the  disposal  of  sewage  and  manure. 

Clothing. — Much   of   the   eflficiency   and   the   comfort   of 


268  FEDERAL  HYGIENE 

the  soldier  will  depend  on  his  clothing,  its  kind,  material, 
weight,  etc.  The  various  articles  of  clothing — hats,  under- 
wear, trousers,  coats,  overcoats,  shoes,  etc. — must  not  only 
be  strong  and  durable,  but  also  light,  well  fitting,  easily 
cleaned,  proper  for  the  climate,  convenient,  and  of  light 
weight  and  proper  color.  Underwear  is  best  made  of  merino, 
or  a  mixture  of  wool  and  cotton,  with  an  extra  flannel  or 
woollen  shirt  carried  for  extra  wear.  The  use  of  two  shirts, 
etc.,  is  recommended  in  cold  weather  instead  of  increasing 
the  weight  of  the  shirts.  Shoes  are  to  be  made  of  water- 
proof leather,  with  broad,  thick  soles,  low  heels,  square 
at  the  toe,  and  not  too  heavy.  Cloth  caps  are  used  in  tem- 
perate climates,  and  should  be  loose  fitting,  light,  durable, 
and  comfortable. 

The  inspection  of  the  clothing  and  its  condition  is  one 
of  the  important  duties  of  the  officers. 

Habitations. — ^The  selection  of  the  places  for  the  temporary 
and  permanent  habitations,  camps,  barracks,  quarters, 
etc.,  and  the  construction  of  these  habitations  is  another 
important  matter  demanding  expert  sanitary  knowledge  on 
the  part  of  the  officers. 

The  selection  of  the  site  with  a  view  to  proximity  of  forest, 
marshes,  watercourses  and  water  supply,  the  preparation 
of  the  sites  and  foundations,  the  planning  of  the  various 
buildings,  and  other  matters  regarding  the  construction 
of  the  whole  camp  cannot  be  gone  into  detail  here,  but  are 
guided  upon  the  general  principles,  some  of  which  have 
been  elucidated  in  the  chapter  on  housing  hygiene.  The 
same  applies  to  the  question  of  proper  ventilation,  air  space, 
lighting  and  heating  of  the  barracks,  etc.  Barracks  and 
squad  rooms  must  not  be  too  large,  not  over  24  feet  wide 
and  14  feet  high,  and  should  provide  at  least  600  feet 
floor  space  for  every  person.  The  care  and  cleanliness  of  the 
habitations,  a  matter  of  importance,  should  be  the  duty  of 
the  soldiers  and  under  the  supervision  of  their  ofiicers. 

Individual  Hygiene  and  Prevention  of  Disease. — ^The  care 
of  the  soldier's  health,  all  matters  pertaining  to  individual 
hygiene,  is  of  the  utmost  importance  in  the  efficiency  of 


QUESTIONS  269 

the  soldier  in  peace  and  war.  The  various  rules  guiding 
the  life  and  haLits  of  the  soldier  must  be  appropriate  to  the 
personnel,  place,  and  climate,  and  must  not  only  be  super- 
vised by  the  officers,  but  must  be  endeavored  to  be  inculcated 
into  the  soldier's  intelligence,  so  that  by  education  he  should 
understand  the  value  of  the  different  precautions  for  the 
preservation  of  his  health  and  for  the  prevention  of  the 
various  diseases  to  which  soldiers  are  especially  subjected. 

QUESTIONS. 

Describe  the  functions  of  federal,  state,  and  municipal  hygiene. 

Name  the  functions  of  the  proposed  Federal  Department  of  Health. 

Define  \'ital  statistics.     WTiat  are  they  based  upon? 

Define  the  foUo-wing  terms:  registration  area,  actual  increment  and 
natural  increment  of  popiilation,  birth  rate,  marriage  rate,  morbidity  rate. 

How   are   the   mortality   rates    calculated? 

What  are  "the  mean  age  at  death,"  "the  probable  duration  of  Ufe," 
and  "expectation  of  hfe"? 

WTiat  is  quarantine?     At  what  times  ie  it  necessarj^? 

WTiat  are  the  essentail  points  of  quarantine  regulations? 

TMiat  are  the  functions  of  naval  hygiene? 

Describe  the  proper  sanitation  of  ships. 

State  the  rules  for  guarding  the  health  of  seamen 

Give  the  principles   of  selection   of  militarj^  recruits. 

State  proper  precautions  in  feeding  soldiers  in  peace  and  in  war. 

Give  rules  for  the  water  supply  and  drainage  of  camps,  etc. 

State  points  important  in  selection  of  soldier's  clothing. 

Give  essential  principles  of  selection  of  camps  jmd  habitations. 

Give  essential  points  of  individual  hygiene  and  prophylaxis. 


INDEX. 


Accidents,  industrial,  98 
causes  of,  99 
number  of,  99 
occurrence  of,  98 
prevention  of,  106 
Acetylene  gas,  illumination  by,  32 
Acquired  immunity,  198 
Actinomycosis,  215 
Active  occupation,  87 
Acute  infectious  conjunctivitis,  216 
Adulteration  of  meat,  124 
Adverse  industrial  conditions,  con- 
trol of,  106 
Age,  occupation  and,  84 

school,  76 
Agglutinins,  200 
Ague,  brass  founders',  95 
Air,  33 

atmospheric,  33 

carbon  dioxide  in,  34 

constituents  of,  33 

contamination  of,  34 

diffusion  of,  34 

examination  of,  in  rooms,  63 

expired,  34 

"fatigue  toxins"  in,  36 

hiunidity  in,  35 

impure,  relation  of,  to  health,  35 

impurities  in,  35 

pressure,  occupation  and,  89 

pure,  amount  of,  needed,  36 
Alexins,  199 

Anchylostomiasis,  98,  216 
Animal  substances,  manufacture  of, 
as  public  nuisance,  188 
prophylaxis  in,  188 
Animals,     condemnation    of,     for 

food,  122,  128 


Animals,  keeping  of,  as  public  nui- 
sance, 185 

sanitary  legislation  for,  185 
Anthracosis,  92 
Anthrax,  201,  218 
Antitoxin,  200,  202 

diphtheria,  202 

tetanus,  202 
Arsenic,  poisoning  with,  94 
effects  of,  94 

portals  of  entry,  94 
Artificial  immunity,  200 

ventilation,  38 
Asepsis,  208 
Attitude  during  occupation,  88 


B 


Bacilli,  pathogenic,  193 
Bacillus  botulinus,  123 
Bacteria,  193 

attenuated,     vaccination     with, 
201 

attenuation  of,  201 

dead,  immunization  with,  201 

in  houses,  50 

infection  of  meat  by,  123 

in  milk,  143 

viabihty  of,  127 

\arulent,  inoculation  with,  201 

in  waste  matter,  165,  166,  167 
Bacterial  processes,  sewage  dispo- 
sal by,  175,  176 

products,     immunization     ^ith, 
201 
Bacteriology^,  science  of,  192 
"Bends,"  89 
Berkefeld  filters,  44 
Birth  rate,  261 

(271) 


272 


INDEX 


Blackboards  in  schools,  75 
Boiling,  disinfection  by,  205 

of  milk,  151 

purification  of  water  by,  44 
Bottles,  milk,  care  of,  150 
Brass  founders'  ague,  95 

poisoning  with,  95 
Brick  as  building  material,  23 
Buildings,  cellars  of,  28 

construction  of,  27 

floors  of,  29 

footings  of,  28 

foundations  of,  28 

materials,  23 

roofs  of,  29 

site  of,  27 

walls  of,  29 
Burial,  172 

Bm-ning,  disinfection  by,  209 
Butter,  142 
ButtermUk,  142 


Caisson  disease,  89 

Carbolic    acid,    disinfection    with, 

211 
Carbon  dioxide,  34 
Carcasses,    diseased,    disposal    of, 

129 
Cardiac    diseases    among    school 

children,  69 
Cement  as  building  material,  23 

natural,  as  building  material,  23 
Central  heating,  41 
Cereals,  135 

Cerebrospinal  meningitis,  219 
Cesspools,  sewage  disposal  by.  46 
Chalicosis,  92 
Cheese,  142 
Chemical  composition  of  food,  120 

preservation  of  food,  132 

purification  of  water,  44 

testing  of  milk,  159 

trades,  dangers  of,  97 
Chicken-pox,  221 
Child  labor,  injin-ious  effects  of,  85 

restriction  of,  106 
Chlorine  in  water,  118 
Cholera,  hog,  222 

water  supply  and,  110 


Chromium,  poisoning  with,  95 

effects  of,  95 
Circulatory  diseases  among  school 

children,  69 
Cleaning,  damp-cloth  method  of, 
53 

dry  method  of,  53 

of  schools,  74 

of  streets,  171 

suction  method  of,  53 

vacuum  method  of,  53 
Cleanlinesc  of  houses,  inspection  of, 

62 
Coal  gas,  illumination  by,  32 
Cocci,  pathogenic,  193 
Cold,  disinfection  with,  208 

storage  of  meat,  131 
Colostrum,  142 
Combined  method  of  ventilation, 

38 
Communicable  diseases,  214 
Concrete  as  building  material,  24 

reinforced,  as  building  material, 
24 
Condensed  milk,  142 
Conjunctivitis,     granular,     among 
school  children,  69 

infectious       catarrhal,      among 
school  children,  69 
Construction  of  houses,  inspection 

of,  57 
Contamination  of  air,  34 
Corrosive    sublimate,    disinfection 

with,  211 
Cows,  care  of,  147 
Cramp,  writer's,  90 
Cream,  142 

gauge,  testing  of  milk  with,  156 
Cremation,  171 
Cresols,  disinfection  with,  211 
Cysticercus  bovis,  122 

ceUulosae,  122 


Dairy  farms,  drainage  of,  145 

surroundings  of,  146 

water  supply  of,  145 
Damp-cloth  method  of  cleaning,  53 
Dampness  of  houses,  25 

causes  of,  25 


INDEX 


273 


Dampness,  health  and,  25 
inspection  of,  57,  62,  63 
prevention  of,  26 
Damp-proof  construction,  26 

Silvester's,  27 
Dead  bodies  as  waste  matter,  165 
Death  rate,  261 
Defective    physical    development, 

schools  and,  67 
Defectives  in  schools,  77 
Dengue,  223 
Deodorant,  208  _ 

Desiccation,  disinfection  with,  209 
Desks  in  schools,  75 
Digestive    diseases    among   school 

children,  70 
Diphtheria,  224 
antitoxin,  202 
Dirt  in  houses,  50 

prophylaxis  against,  51 
Diseases,  bacterial,  193 
definitions  of,  190 
industrial,  classes  of,  100 
infectious,  definition  of,  191 
morbific  agents  of,  192 
destruction  of,  206 
notification  of,  203 
portals  of  entry  of,  194 
prophylaxis  of,  197 
public  measures  against,  205 
reporting  of,  203 
social  measures  against,  202 
stages  of,  191 
treatment  of,  204 
school,  69 

unfitting  animals  for  food,  129 
Disinfectant,  208 
chemical,  210 
gaseous,  212 
physical,  209 
Disinfection,  208 

of  houses,  53 
Distillation,   purification  of  water 

by,  44 
Domestic  animals,  health  and,  51 
Drainage,  45 

of  dairy  farms,  145 
Dry  method  of  cleaning,  53 

rot  in  houses,  50 
Dust,  91 

classification  of,  92,  93 
effect  of,  upon  health,  91 
18 


Dust,  effect  of,  upon  lungs,  92 

in  factories,  102 

in  houses,  50 

as  public  nuisance,  181 
Dysentery,  amebic,  225 

bacillary,  226 


E 


Earth  closets,  sewage  disposal  by, 

45 
Echinococcus  infection,  123 
Effluvia  as  public  nuisance,  184 
Eggs,  135 

Electric  light,  illumination  by,  32 
Electricity,  sewage  disposal  by,  175 
Embalming,  171 
Environment,     industrial,     public 

control  of,  107 
Evaporated  milk,  142 
Examinations  in  schools,  77 
Exercise  in  schools,  78 
Exhaustion  method  of  ventilation, 

38 


Factories,  86 

ceilings  of,  101 

construction  of,  101 

dust  in,  102 

floors  of,  101 

inspection  of,  107 
medical,  107 

lighting  of,  101 

size  of,  101 

ventflation  of,  102 

waUs  of,  101 

water  supply  of,  101 
Fatigue  neuroses,  90 

prevention  of,  ill-effects  of,  106 

toxins  in  air,  36 

work  and,  89 
Favus,  227 
Federal  hygiene,  257 
Feeding,  proper,  schools  and,  76 
Field  irrigation,  sewage  disposal  by, 

46 
Fflters,  Berkefeld,  44 
Filtration,  intermittent  sofl,  sewage 

disposal  by,  174 


274 


INDEX 


Filtration,  purification  of  water  by, 

44,  114 
Fire  escapes,  25 
extinguishers,  25 
protection,  24 
Fireproofing,  24 

of  houses,  inspection  of,  58 
methods  of,  24 
Fish,  134 

Fhes,  typhoid  fever  and,  51 
Flushometer,  Kenney,  49 
Food  animals,  diseases  of,  123 
examination  of,  126 
inspection  of,  126 
postmortem  changes  in,  124 
sanitary  care  for,  125 
tuberculin  tests  for,  126 
,  unfitness  of,  for  food,  124 
chemical  composition  of,  120 
classification  of,  120 
meat,  120 

public  health  and,  122 
supply,  120 

trade,  regxilation  of,  187 
Foodstuff  standard,  154 
Foremilk,  142 
Formaldehyde     gas,     disinfection 

with,  212 
Fruit,  135 
Fumes,  industrial,  96 

prophylaxis  against,  103 
as  public  nuisance,  182 
Furnace  heating,  41 
Furniture  in  schools,  74 


G 


Galton  grates,  40 
Game,  133 
Garbage,  49 
Gas,  sewer,  47 
Gases,  industrial,  96 

prophylaxis  against,  103 

as  public  nuisance,  182 
Gastro-intestinal     diseases,     milk 

supply  and,  139 
German  measles,  228 
Germicide,  208 
Glanders,  228 
Gonorrhea,  230 
Grates,  Galton,  40 


Grates,  heating  by,  40 
Growth,  effect  of  schools  on. 


"Hard"  water,  43 
Health  legislation  and  administra- 
tion, 257 
pubhc,  17 
Heat,  disinfection  by,  209 
dry,  disinfection  by,  209 
Heating,  38 
central,  41 
furnace,  41 
by  grates,  40 
hot-air,  41 
hot-water,  41 

of  houses,  inspection  of,  69 
local,  40 
means  of,  39 
methods  of,  39 
proper  amount  of,  39 
of  schools,  73 
steam,  42 
by  stoves,  40 
Home  influences,  school  and,  75 
work,  106 

restriction  of,  106 
Hot-air  heating,  41 
Hot-water  heating,  41 
Household  waste,  49 
Houses,  arrangement  of,  30 
bacteria  in,  50 
cleaning  of,  49 
dampness  of,  25 
dirt  in,  50 
disinfection  of,  53 
dry  rot  in,  50 
dust  in,  50 
impurities  in,  49 
inspection  of,  55 

cleanliness  of,  62 

construction  of,  57 

dampness  of,  57 

fireproofing  of,  58 

heating  of,  59 

plumbing  of,  60 

special,  62 

surroundings,  56 

ventilation  of,  59 

water  supply  of,  60 


INDEX 


275 


Houses,  microorganisms  in,  50 

plans  of,  30 

refuse  of,  disposal  of,  170 

receptacles    for  collection   of, 
171 
Housing,   defective   conditions  in, 
54 
remedies  for,  55 

health  and,  22 

hygiene  of,  22 

problem,  54 
Humidity  in  air,  35 

occupation  and,  88 

relative,  64 
Hygiene,  aim  of,  17 

definition  of,  17 

federal,  257 

function  of,  17 

industrial,  80 

mihtary,  264 

municipal,  258 

naval,  263 

origin  of,  18 

personal,  17 
of  workers,  105 

public,  17 

school,  67 


Illumination  by  acetylene  gas,  32 

artificial,  32 

by  coal  gas,  32 

by  electric  light,  32 

by  water  gas,  33 
Immunity,  198 

acquired,  198 

artificial,  200 

causes  of,  199 

natural,  198 

passive,  201 
Immunization  with  bacterial  prod- 
ucts, 201 

with  dead  bacteria,  201 
Impurities  in  air,  34 
Indoor  work,  85 
Industrial  accidents,  98 

conditions,  adverse,  87 

diseases,  100 

dusts,  91 

fumes,  96 

gases,  96 


Industrial  hygiene,  SO 
infections,  97 

insurance,  compulsory,  107 
poisons,  93 
prophylaxis,  100 
vapors,  96 
waste  matter,  165 
Industries,  effect  of,  on  health,  81 
Infant  mortality,  137,  138 

gastro-intestinal  diseases  and, 

138 
milk  supply  and,  137 
rate,  261 
Infection,  echinococcus,  123 
by  fomites,  197 
industrial,  97 
transmission  of,  195 
by  air,  197 
by  animals,  196 
by  food,  196 
by  insects,  196 
by  pathogenic  germs,  167 
by  soil,  197 
Infectious  diseases  among  school 
children,  69 
milk  supply  and,  139 
prevention  of,  190 
Inoculation  with  virulent  bacteria, 

201 
Insecticide,  208 
Inspection,  factory,  107 
of  houses,  55 
of  meat,  126 
of  milk,  154 
of  water,  116 
Insurance,    compulsory  industrial, 

107 
Irrigation,  sewage  disposal  by,  175 
subsoil,  sewage  disposal  by,  175 


Kenney  fiushometer,  49 
Komnyss,  142 


Lactometer,  Quevenne's,   testing 
of  milk  with,  157 
testing  of  milk  with,  158 


276 


INDEX 


Lactoscope,  testing  of  milk  with, 

156 
Lead,  poisoning  with,  93 
effect  of,  94 
portals  of  entry  of,  94 
workers,  mortality  of,  94 
Legislation,  sanitarj-,  257 
administration  of,  257 
municipal,  258 
state,  258 
Leprosy,  231 
Life,  expectation  of,  262 

human,  economic  value  of,  20 

increase  of  length  of,  19 
probable  duration  of,  262 
Light,  natural,  31 

occupation  and,  88 
Lighting,  31 
of  factories,  101 
of  schools,  73 
Lime,  common,  as  building  mate- 
rial, 23 
disinfection  with,  211 
Local  heating,  40 
Lungs,  effect  of  dust  upon,  92 


M 

Malaria,  232 

mosquitoes  and,  51 
Marriage  rate,  261 
Measles,  233 

Meat,  adidteration  of,  124 
prevention  of,  132 
diseases   transmissible   tlu-ough, 

123 
dr^dng  of,  131 
foods,  120 
health  and,  120 
infection  of,  by  bacteria,  123 
by  persons  and  places,  124 
inspection  of,  antemortem,  128 
disposal  of  diseased  carcasses 

in,  129 
Government    regulations    for, 

128 
Law,  Federal,  126 
postmortem,  128 
parasitic  diseases  and,  122 
preservation  of,  131 
chemical,  132 


Meat,  preservation  of,   condimen- 
tal,  131 
by  heat,  132 
ptomains  in,  123 
sanitary  supervision  of,  132 
by  smoking  of,  131 
ptomains  in,  123 
storage  of,  131 

cold,  131 
toxins  in,  123 
unfitness  of,  for  food,  123 
wholesome,     characteristics    of, 
130 
Mechanical  ventilation,  37,  38 
Medical  super\asion  of  schools,  78 
Medicine,  state,  17 
Mercury,  poisoning  with,  94 
effects  of,  95 
portals  of  entrj^  of,  95 
Metal  in  water,  119 
IMicrobes,    pathogenic,    in    water 

supply,  109 
Microorganisms,  193 

in  houses,  50 
Military  hj^giene,  264 
Milk,  adulteration  of,  145 
bacteria  in,  143 
number  of,  143 
varieties  of,  144 
bacteriologic  examination  of,  154 
boiling  of,  151 
bottles  for,  care  of,  150 
care  of,  after  milking,  148 
changes  in,  chemical,  144 

on  standing,  144 
chemical  examination  of,  154 
condensed,  142 
cow's,  141 

composition  of,  141 
evaporated,  142 
inspection  of,  154,  159 
pasteurization  of,  151 
advantages  of,  152 
disadvantages  of,  152 
phj'sical  characters  of,  143 
examination  of,  154,  155 
phj'siology  of,  141 
preservation  of,  150 
reaction  of,  143 
samples  of,  for  testing,  155 
specific  gravity  of,  143 
standard  of,  154 


INDEX 


277 


Milk,  sterilization  of,  151 
supply,  clean,  production  of,  145 
contamination  of,  sources  of, 

140 
disease  and,  138 
gastro-intestinal  diseases  and, 

139 
infant  mortality  and,  137 
infectious  diseases  and,  139 
public  health  and,  137 
sanitary  supervision  of,  153 
tuberculosis  and,  139 
testing  of,  154 
chemical,  159 
with  cream  gauge,  156 
with  lactometer,  158 

Que  venue's,  157 
with  lactoscope,  156 
with  pioscope,  156 
by  specific  gravity,  157 
Milking,  148 
Morbidity  rate,  261 
Mortality  rate,  decrease  of,  19 

from   preventable   diseases, 
20 
Mosquitoes,  malaria  and,  51 

yellow  fever  and,  51 
Mouth,  diseases  of,  among  school 

children,  72 
Mumps,  234 
Myopia  among  school  children,  69 


N 


Natural  immunity,  198 

hght,  31 

ventilation,  37 
Naval  hygiene,  263 
Nervous    diseases    among    school 
children,  70 

fatigue,  90 
Nitrates  in  water,  118 
Nitrites  in  water,  118 
Noise,  avoidable,  180 

industrial,  180 

prevention  of,  180 

as  public  nuisance,  179 

street,  179 
Nose,    diseases   of,    among   school 

children,   69 


Notification  of  infectious  diseases, 

203 
Nuisances,  public,  178 

animals,  keeping  of,  185 

definition  of,  178 

dust,  181 
.      effluvial,  184 

fumes,  182 

gases,  182 

noise,  179 

odors,  184 

sanitary,  178 

slaughter  houses,  186 

smoke,  181 

waste  matters,  182 
Nuts,  135 


Occupation,  active,  87 

age  and,  84 

air  pressure  and,  89 

attitude  during,  88 

effect  of,  on  women,  83,  84 

extremes  of  temperature  and,  87 

health  and,  80 

humidity  and,  88 

Hght  and,  88 

personal  factors  in,  82 

position  during,  88 

sedentary,  87 

sex  and,  83 
Odors  as  pubUc  nuisances,  184 
Opsonic  index,  200 
Opsonins,  199 
Outdoor  work,  85 
Overcrowding,  mortality  rate  and, 
22 

of  schools,  78 


Packing  houses,  sanitation  of,  126 
Pail  system  of  sewage  disposal,  45 
Parasites,  51 

Parasitic  diseases,  meat  foods  and, 
122 
ova  in  water  supply,  109 
Passive  immunity,  201 
Pasteurization  of  milk,  151 
Pathogenic  microbes  in  water  sup- 
ply, 109 


278 


INDEX 


Peppermint  test,  61 
Personal  hygiene,  17 
Pettenkoffer's  test,  63 
Phagocytes,  199 
Phosphorus,  poisoning  with,  95 

effect  of,  95 
Pioscope,  testing  of  milk  with,  15G 
Plague,  bubonic,  septicemic,  pneu- 
monic, 236 
Plenum  method  of  ventilation,  38 
Plumbing,  45 

essentials  of,  46 

in  houses,  inspection  of,  60 

in  schools,  74 
Pneumokoniosis,  92 
Pneumonia,  acute  lobar,  238 
Poisons,  industrial,  93 

prophylaxis  against,  103 
Poliomyelitis,  239 
Population,  increment  of,  261 
Position  during  occupation,  88 
Poultry,  133 
Precipitation,  sewage  disposal  by, 

174 
Privy  vaults,  sewage  disposal  by, 

45 
Progress,  sanitary,  19 
Prophylaxis,  industrial,  100 
Propulsion  method  of  ventilation, 

38 
Ptomains  in  meat,  123 
Public  health,  17 

hygiene,  17 
Purification  of  water,  44,  114 
chemical,  114 


QUAKANTINE,  262 


Rabies,  240 

Rag  sorter's  disease,  98 

Rain,  164 

water,  43 

disposal  of,  168 
Rats,  destruction  of,  52 
Refuse,  house,  165 

street,  164 
Reporting   of   infectious    diseases, 

203 


Respiratory  diseases  among  school 

children,  69 
Rooms,  disinfection  of,  213 

window  area  of,  31 


S 


Sanitary  legislation,  257 

progress,  19 
Sanitation,  17 

art  of,  17 

science  of,  17 
Scarlet  fever,  242 
School  age,  76 

blackboards  in,  75 

children,  diseases  of,  69 

cleaning  of,  74 

construction  of,  71 

defective  physical  development 
and,  67 

defectives  in,  77 

desks  in,  75 

diseases,  69 

effect  of,  on  growth,  68 
on  weight,  68 

examination  in,  77 

exercise  in,  78 

furniture  in,  74 

heating  of,  73 

home  influences  and,  75 

hours,  76 

hygiene,  67 

life,  ill-effects  of,  58,  61 

lighting  of,  73 

medical  supervision  of,  77,  79 

methods  of  study  in,  77 

multiphcity  of  studies  in,  77 

overcrowding  of,  78 

plumbing  in,  74 

proper  feeding  and,  76 

relation  of,  to  health,  67 

seats  in,  75 

sites  of,  71 

ventilation  of,  73 

water  supply  of,  74 
Sedentary  occupation,  87 
Sedimentation,       purification       of 

water  by,  44,  114 
Septic  process,  sewage  disposal  by, 
176 

sore-throat,  243 


INDEX 


279 


Sewage,  49 

disposal  of,  45,  172 
by  bacterial  processes,  175,  176 
by  cesspool,  46 
by  earth  closets,  45 
by  electricity,  175 
by  field  irrigation,  46 
by  intermittent  soil  filtration, 

174 
by  irrigation,  175 

subsoil,  175 
methods  of,  174 
by  pail  system,  45 
by  precipitation,  174 
by  privy  vaults,  45 
by  septic  processes,  176 
as  waste  matter,  166 
'"Sewer  gas,"  prevention  of  admis- 
sion of,  47 
Sewerage,  combined  system  of,  168 

separate  system  of,  169 
Sex,  occupation  and,  83 
Siderosis,  92 

Silvester's    damp-proof    construc- 
tion, 27 
SIdm  milk,  142 

Skin  diseases  among  school  chil- 
dren, 70 
Slaughter   houses   as    public    nui- 
sance, 186 
Smallpox,  244. 
Smith's,  Angus,  test,  64 
Smoke  as  pubHc  nuisance,  181 
Snow,  164 

disposal  of,  169 
"Soft"  water,  43 
Soldiers,  examination  of,  264 
Spinal  diseases  among  school  chil- 
dren, 70 
Spirilla,  pathogenic,  193 
Spontaneous  ventilation,  36 
State  medicine,  17 
Statistics,  vital,  259 
census,  259,  260 
records  of,  259 
registration  for,  260 
Steam,  disinfection  by,  209 
Steam  heating,  42 
Sterihzation,  208 

of  milk,  151 
Stone  as  building  material,  23 
Storage  of  meat,  131 


Stoves,  heating  by,  40 
Street-cleaning  problem,  169 
Street  noises,  179 

refuse,  170 
Strippings,  142 

Study,  methods  of,  in  schools,  77 
Subsoil  water,  43 
Subsurface  work,  86 
Suction  method  of  cleaning,  53 
Sulphur  dioxide,  disinfection  with, 

212 
Sunlight,  disinfection  with,  208 
Sweat-shop  work,  86 
SyphUis,  245 


Tabacosis,  92 

Taenia  echinococcus,  123 

saginata,  122 

solium,  122 
Tapeworm,  122 

Temperature,    extremes   of,    occu- 
pation and,  87 

proper,  for  rooms,  39 
Terra-cotta  as  building  material,  23 
Testing  of  milk,  154 
Tetanus,  246 

antitoxin,  202 
Throat,  diseases  of,  among  school 

children,  69 
Tick  fever,  241 
Toxins  in  meat,  123 
Trachoma,  247 

among  school  children,  69 
Trade,  chemical,  dangers  of,  97 

tuberculosis  and,  104 

waste,  disposal  of,  171 
Training,  manual,  105 
Traps,  47 

fouling  of,  48 

seals  of,  47 

unsealing  of,  47 
Trichina  spiralis,  122 
Trichinosis,  248 
Tuberculin  tests  for  food  animals, 

126 
Tuberculosis,  89 

milk  supply  and,  139 

pulmonary,  249 

selection  of  trade  and,  104 


280 


INDEX 


Typhoid  fever,  251 

flies  and,  51 

water  supply  and,  112 
Typhus  fever,  253 


V 


Vaccination  with  attenuated  bac- 
teria, 201 

Vacuum  method  of  cleaning,  53 
of  ventilation,  38 

Vapors,  industrial,  96 . 

Vegetables,  135 

Ventilation,  36 
of  factories,  102 
of  houses,  inspection  of,  59 
methods  of,  37,  38 
of  schools,  73 
of  ships,  263 

Vermin,  51 


W 

Waste,  household,  49 
matter,  bacteria  in,  165 

dead  bodies,  165 

disposal  of,  168 

effluvia  of,  167 

gases  in,  167 

house  refuse,  165 

hygienic  importance  of,  106 

industrial,  165 

infection  in,  167 

odors  of,  167 

public  health  and,  164 
nuisance,  182 

rain,  164 

sewage,  166 

snow,  164 

street  refuse,  164 
water,  49 
Water,  chemically  pure,  112 
chlorine  in,  118 
closets,  49 
"hard,"  43 
inspection,  116 
metals  in,  119 
nitrates  in,  118 
nitrites  in,  118 
purification  of,  44 


Water,  rain,  43 
"soft,"  43 
subsoil,  43 
supply,  42 

cholera  and,  110 
of  dairy  farms,  145 
of  factories,  101 
of  horses,  inspection  of,  60 
infection  of,  source  of,  112 
parasitic  ova  in,  109 
pathogenic  microbes  in,  109 
public,  109 

purification  of,  114 
source  of,  123 
purity  of,  42 

relation  of,  to  health,  109 
of  schools,  74 

sources  of,  inspection  of,  117 
typhoid  fever  and,  101 
water-borne  diseases  and,  101 
sm-face  collection  of,  43 
waste,  49 
well,  43 
Water-borne  diseases,  112 
Water-gas,  illumination  by,  33 
Weight,  effect  of  schools  on,  68 
Well  water,  43 
Wells,  inspection  of,  117 
"Welsbach"  lights,  32 
Whey,  142 

Whooping  cough,  254 
Window  area  of  rooms,  31 
Wolpert's  test,  64 
Women,  labor  of,  restriction  of,  105 
Wood  as  a  building  material,  22 
Work,  compensation  for,  91 
home,  86 
indoor,  85 
injurious  effects  of,  on  children, 

85 
outdoor,  85 
subsurface,  86 
"sweat  shop,"  86 
Workplace,  sanitation  of,  101 
Workshops,  86 
Writer's  cramp,  90 


Yellow^  fever,  255 
mosquitoes  and,  51 


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„■«,•>  «  ri  1' 

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RA425 
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Jygj^e^^e  and  public  health. 


P93 
1919 


Py3 


.^'■.'-  .J" 


m 


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1.  i.L'. 


